5,681 research outputs found
An introduction of dominant genes in genetic algorithm for scheduling of FMS
This paper proposed a new idea named Dominant Genes (DGs) in Genetic Algoriths (GAs) to deal with FMS scheduling problem with alternative production routing. In traditional GAs approach, the crossover mechanism will randomly select a number of genes to undergo crossover. However, these selected genes may not contain or contain only part of the critical structure of its original chromosome. In addition, since the inherited complexity of the scheduling nature, the changes in the structure of the selected genes will further influence its strength. To tackle this problem, the proposed DGs in this paper are to identify and record the best genes in the chromosome. A new crossover mechanism is also designed to ensure the best genes will undergo crossover, and retain the originality of the structure of the crossover genes. The performance of the proposed DGs is testified by comparing it with other heuristic optimizations. The shows that DGs perform better than other approaches. ©2005 IEEE.published_or_final_versio
Separation of a benzene and nitric oxide mixture by a molecule prism
A study was performed on the separation of nitric oxide and benzene mixture by a molecule prism. The energy conservation and wave properties of molecules were used to obtain the molecule-optical index of refraction for a nonresonant infrared laser pulse. A chromatographic resolution of 0.62 for the spatial separation of a mixture was obtained using the focused Nd:YAG laser pulse as a molecule prism.open273
Word learning deficit among Chinese dyslexic children
The present study examined word learning difficulties in Chinese dyslexic children, readers of a nonalphabetic script. A total of 105 Hong Kong Chinese children were recruited and divided into three groups: Dyslexic (mean age 8;8), CA control (mean age 8;9), and RL control (mean age 6;11). They were given a word learning task and a familiar word writing task. It was found that the Dyslexic group performed less well than the RL group in learning irregular words over trials but not the regular ones. Error analyses showed that the Dyslexic group made more orthographic and word association errors but less intra-wordlist interference errors than the RL control group. The Dyslexic group also performed significantly less well than both control groups in writing familiar words (e.g. their own name). These findings suggest that Chinese dyslexic children have difficulty learning new words, especially irregular ones, and retaining overlearned words in long-term memory. We conclude that Chinese dyslexic children have a specific impairment in word learning like their alphabetic counterparts. © 2006 Cambridge University Press.published_or_final_versio
Estimating incidence of developmental dyslexia in Hong Kong: What differences do different criteria make?
Based on the data of a school-referred sample of Cantonese-speaking Chinese children who met the Hong Kong criterion of dyslexia, we estimated for developmental dyslexia of Chinese children aged between 6 and 10½ in Hong Kong an incidence rate of 0.66% and a gender ratio of 3.29 boys to 1 girl over a four-year period. We also explored the differences in estimates based on this Hong Kong criterion that emphasizes cognitive markers with more conventional discrepancy-based criteria. In view of the possible biases in self-selection and underreporting in the data of the school-referred sample, we compared the figures with those derived from the sample of the normative study of the Hong Kong Test of Specific Learning Difficulties in Reading and Writing, which yielded an estimate of 9.7% in prevalence rate and boy-girl gender ratio of 2 to 1 over a one-year period. The differences in estimates based on the two samples and implications of the findings are discussed in light of the limitations of the study.postprin
Screening for Chinese children with dyslexia in Hong Kong: The use of the teachers' behaviour checklist
Primary school teachers rated the frequency of occurrence of 65 reading-related behavioural characteristics in a sample of 251 Grade 1 to Grade 6 Chinese school children in Hong Kong. These behavioural characteristics were in the areas of general performance, reading, dictation, writing, mathematics, language, memory, concentration, sequential ability, motor co-ordination, spatial orientation, and social/emotional adjustment. Of these 12 areas, 10 yielded scale scores that could distinguish children with dyslexia from those without dyslexia, identified on the basis of their performance in five domains of literacy and cognitive skills. Using a summary score derived from the 10 relevant scales, an optimal cut-off score was suggested to arrive at a balance between high sensitivity and an acceptable rate of false positives in screening for children with dyslexia. The need for cross-replication in screening children with dyslexia using the behaviour checklist with different samples of school students is emphasised.published_or_final_versio
Development of stable marker-free nuclear transformation strategy in the green microalga Chlorella vulgaris
Although microalgae have valuable resources with great necessity in many biotechnological applications, no tools have been developed yet for a stable genetic transformation without antibiotic marker genes in these organisms. Chlorella is one of the most useful genus for biotechnological applications. The transfer of foreign DNA (vector or linear DNA cassette) into Chlorella by electroporation has very low stability and it is hard to screen the transformants without antibiotic marker genes. However, the marker genes have some disadvantages to host cells. To avoid the negative effects caused by the marker genes, we tried to develop a stable marker-free nuclear transformation system in Chlorella. For this, linear gene expression cassettes (LGEC) were constructed with functional domains, which are responsible for transformation, of SV40 large T antigen. The LGECs were transferred into Chlorella via electroporation and durability of the LGECs were confirmed in transgenic Chlorella. Transcription levels of the LGECs were also determined at different cell cycle sates. The LGECs integrated into the chromosomal DNA of Chlorella were stably replicated and were expressed successfully at G0-, G1-, and G2-phases. This study presents a stable marker-free nuclear transformation system with potential for biotechnological applications.Key words: Chlorella vulgaris, marker-free nuclear transformation, SV40 large T antigen, microalga
Effect of B on the microstructure and mechanical properties of mechanically milled TiAl alloys
The present study is concerned with gamma-(Ti52Al48)(100-x)B-x (x = 0, 0.5, 2, 5) alloys produced by mechanical milling/vacuum hot pressing (VHPing) using melt-extracted powders. Microstructure of the as-vacuum hot pressed (VHPed) alloys exhibits a duplex equiaxed microstructure of alpha(2) and gamma with a mean grain size of 200 nm. Besides alpha(2) and gamma phases, binary and 0.5 pet B alloys contain Ti,AIN and Al2O3 phases located along the grain boundaries and show appreciable coarsening in grain and dispersoid sizes during annealing treatment at 1300 degrees C for 5 hours. On the other hand, 2 pet B and 5 pet B alloys contain fine boride particles within the gamma grains and shaw minimal coarsening during annealing. Room-temperature compressing tests of the as-VHPed alloys show low ductility, but very high yield strength > 2100 MPa. After annealing treatment, mechanically milled alloys show much higher yield strength than conventional powder metallurgy and ingot metallurgy processed alloys, with equivalent ductility to ingot metallurgy processed alloys. The 5 pet B alloy with the smallest grain size shows higher yield strength than binary alloy up to the test temperature of 700 degrees C. At 850 degrees C, 5 pet B alloy shows much lower strength than the binary alloy, indicating that the deformation of fine 5 pet B alloy is dominated by the grain boundary sliding mechanism.ope
Increased burden of cardiovascular disease in people with liver disease: unequal geographical variations, risk factors and excess years of life lost
BACKGROUND: People with liver disease are at increased risk of developing cardiovascular disease (CVD), however, there has yet been an investigation of incidence burden, risk, and premature mortality across a wide range of liver conditions and cardiovascular outcomes. METHODS: We employed population-wide electronic health records (EHRs; from 1998 to 2020) consisting of almost 4 million adults to assess regional variations in disease burden of five liver conditions, alcoholic liver disease (ALD), autoimmune liver disease, chronic hepatitis B infection (HBV), chronic hepatitis C infection (HCV) and NAFLD, in England. We analysed regional differences in incidence rates for 17 manifestations of CVD in people with or without liver disease. The associations between biomarkers and comorbidities and risk of CVD in patients with liver disease were estimated using Cox models. For each liver condition, we estimated excess years of life lost (YLL) attributable to CVD (i.e., difference in YLL between people with or without CVD). RESULTS: The age-standardised incidence rate for any liver disease was 114.5 per 100,000 person years. The highest incidence was observed in NAFLD (85.5), followed by ALD (24.7), HCV (6.0), HBV (4.1) and autoimmune liver disease (3.7). Regionally, the North West and North East regions consistently exhibited high incidence burden. Age-specific incidence rate analyses revealed that the peak incidence for liver disease of non-viral aetiology is reached in individuals aged 50–59 years. Patients with liver disease had a two-fold higher incidence burden of CVD (2634.6 per 100,000 persons) compared to individuals without liver disease (1339.7 per 100,000 persons). When comparing across liver diseases, atrial fibrillation was the most common initial CVD presentation while hypertrophic cardiomyopathy was the least common. We noted strong positive associations between body mass index and current smoking and risk of CVD. Patients who also had diabetes, hypertension, proteinuric kidney disease, chronic kidney disease, diverticular disease and gastro-oesophageal reflex disorders had a higher risk of CVD, as do patients with low albumin, raised C-reactive protein and raised International Normalized Ratio levels. All types of CVD were associated with shorter life expectancies. When evaluating excess YLLs by age of CVD onset and by liver disease type, differences in YLLs, when comparing across CVD types, were more pronounced at younger ages. CONCLUSIONS: We developed a public online app (https://lailab.shinyapps.io/cvd_in_liver_disease/) to showcase results interactively. We provide a blueprint that revealed previously underappreciated clinical factors related to the risk of CVD, which differed in the magnitude of effects across liver diseases. We found significant geographical variations in the burden of liver disease and CVD, highlighting the need to devise local solutions. Targeted policies and regional initiatives addressing underserved communities might help improve equity of access to CVD screening and treatment
Direct ink writing of polycaprolactone / polyethylene oxide based 3D constructs
There has been increasing interest over recent years in the application of three-dimensional (3D) printing technologies in the biomedical field. One such method is Direct Ink Writing (DIW); this approach has the potential advantage of allowing room-temperature deposition of materials, presented as an ink, to build complex architectures. DIW offers the ability to process biomaterials containing temperature-sensitive components. Due to the fabrication principles of DIW, there are specific rheological requirements that the ink must exhibit for the 3D construction. For this reason, hydrogel-based liquid feed stocks have been the focal point of ink development. As a consequence, studies based on inks comprising hydrophobic biomaterials, which are insoluble in water and hence unsuited to the hydrogel approach, have been limited.
In this study, we investigate novel inks that utilize polycaprolactone (PCL), a hydrophobic polymer, as the primary constituent by dissolving the polymer in solvent systems based on dichloromethane (DCM) and acetone (ACE). Moreover, polyethylene oxide (PEO) was incorporated into the PCL systems in order to extend the range of hydrophilicity of the systems. The rheological properties of the inks were investigated as a function of polymer composition and solvent system. Woodpile constructs of PCL and PCL/PEO were fabricated using DIW method and were assessed by a series of material characterisation. The type of solvent system had a noticeable impact on the ink rheology, which ultimately affected the surface properties. The incorporation of PEO particularly enhanced the roughness and wettability of the constructs. Our results support the use of DIW as a new means to process hydrophobic polymers for biomedical applications
Molecular lens applied to benzene and carbon disulfide molecular beams
A molecular lens of the nonresonant dipole force formed by focusing a nanosecond IR laser pulse has been applied to benzene and CS2 molecular beams. Using the velocity map imaging technique for molecular ray tracing, characteristic molecular lens parameters including the focal length (f ), minimum beam width (W), and distance to the minimum beam width position (D) were determined. The laser intensity dependence of the observed lens parameters was in good agreement with theoretical predictions. W was independent of the laser peak intensity (I-0), whereas f and D varied linearly with 1/I-0. The differences in lens parameters between the molecular species were well correlated with the polarizability per mass values of the molecules. A high chromatographic resolution of Rs = 0.84 was achieved between the images of benzene molecular beams undeflected and deflected by the lens. The possibilities for a new type of chromatography are discussed.open293
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