Research directions for high-performance concrete

The Conference program's website is located at http://hkie.cvd.annualconference.i-wanna.com/program.htmlSession 4: Construction Technology and Material SelectionThe continuous development of civil infrastructure has been imposing more and more stringent requirements on the concrete to be used. To meet with stringent requirements, the notion of high-performance concrete (HPC) processing high strength, high workability, high durability and high dimensional stability had been put forward in the last century. After about 20 years of development, a large variety of HPC has been produced. However, since the various performance attributes of HPC are often contradictory to each other and thus difficult to achieve simultaneously, the development of HPC has come to a bottle neck. To cope with such situation, a more scientific approach is needed. Here, we shall explain how conventional concrete technology could be reformed into modern concrete science by incorporating new theories on particle packing, water film thickness and particle interaction. We shall also introduce new technologies such as aggregate treatment, fillers and green concrete. It is our belief that with further advancement in concrete science and technology, even better HPC could be produced for more sustainable construction.postprin

The GENVABO study – genetic variants as biomarkers of jaw osteonecrosis associated with bisphosphonates: a large, multicentre genome-wide association study and detailed analyses of clinical phenotype

Osteonecrosis of the jaw (ONJ) is a potentially severe adverse effect of bisphosphonates. It can cause persistent pain and infection to the jawbones, and is currently considered incurable. ONJ occurs in a subset of individuals exposed to bisphosphonates (≤7%). Although a number of clinical risk factors, such as dentoalveolar surgery and dental infection, can increase the risk of ONJ development, there remains a number of patients who do not present with these clinical risk factors. Therefore, a genetic predisposition has been proposed. Genome-wide association studies (GWAS), widely performed in pharmacogenomics and successful in other drug side effects, have also been attempted in bisphosphonates-associated ONJ. However, possibly due to small cohort sizes (≤30 cases), these studies failed to detect any significant genetic risk factors. The aim of this thesis is to present the results of a large, multicentre GWAS, coupled with detailed analyses of clinical phenotype. 393 ONJ cases were recruited from 23 clinical centres worldwide. All cases were thoroughly phenotyped and adjudicated by specialist multidisciplinary teams. Random effects logistic regressions (Stata v12.1) were used for clinical risk factor analyses. All samples were genotyped using Illumina® Human1M Omni Express Beadchip (1,072,820 probes) and were compared with 2,554 genetically-matched population controls from publicly available sources. Genotype statistical analysis was performed in PLINK. Risk factors including advanced age, longer bisphosphonates duration, other cancers and use of steroids were found statistically significant (p<0.05). With extreme phenotyping, i.e. non-surgery triggered ONJ cases versus the population controls, for the first time, a genome-wide significant single nucleotide polymorphism was identified: rs12440268 at TJP1 gene (p=1.21E-8). Individuals positive for this marker were nearly three times more likely to develop ONJ than those negative for it (OR=2.66). TJP1 encodes protein at the tight junctions, which maintain epithelial integrity. Its polymorphism may contribute to ONJ pathogenesis through impaired mucosal healing

Pharmacogenetics of Bisphosphonate-associated Osteonecrosis of the Jaw

Osteonecrosis of the jaws (ONJ) is a potentially severe disorder that develops in a subgroup of individuals who have used bisphosphonate (BP) medications. Several clinical risk factors have been associated with the risk of ONJ development, but evidence is limited and in most instances ONJ remains an unpredictable adverse drug reaction. Interindividual genetic variability can contribute to explaining ONJ development in a subset of BP users and the discovery of relevant associated gene variants could lead to the identification of individuals at higher risk. No genetic variant has been found to be robustly associated with susceptibility to ONJ

Factors associated with loss of white matter anisotropy in post-treatment medulloblastoma survivors

We evaluate effects of age at cranial irradiation, time interval since irradiation and irradiation dose on white matter anisotropy in childhood medulloblastoma survivors by computing white matter fractional anisotropy (WM FA) using SPM post-processing functions. Mean percentage change in WM FA of patients compared to controls was -4.4% (sd=7.6%). Using Spearmanís correlation, there were significant associations between percentage reduction of WM FA and age at cranial irradiation (r=0.673, p=0.002) and irradiation dose (r=-0.723, p=<0.001), but not with time interval since irradiation. Multivariate regression analysis confirmed that both factors correlated significantly with percentage reduction of WM FA (adjusted r2=0.516, p=0.001).published_or_final_versio

Increase in methicillin-resistant Staphylococcus aureus acquisition rate and change in pathogen pattern associated with an outbreak of severe acute respiratory syndrome

Background. An outbreak of severe acute respiratory syndrome (SARS) occurred in our 22-bed intensive care unit (ICU; Prince of Wales Hospital, Hong Kong, HKSAR, China) from 12 March to 31 May 2003, when only patients with SARS were admitted. This period was characterized by the upgrading of infection control precautions, which included the wearing of gloves and gowns all the time, an extensive use of steroids, and a change in antibiotic prescribing practices. The pattern of endemic pathogenic organisms, the rates of acquisition of methicillin-resistant Staphylococcus aureus (MRSA), and the rates of ventilator-associated pneumonia (VAP) were compared with those of the pre-SARS and post-SARS periods. Methods. Data on pathogenic isolates were obtained from the microbiology department (Prince of Wales Hospital). Data on MRSA acquisition and VAP rates were collected prospectively. MRSA screening was performed for all ICU patients. A case of MRSA carriage was defined as an instance in which MRSA was recovered from any site in a patient, and cases were classified as imported or ICU-acquired if the first MRSA isolate was recovered within 72 h of ICU admission or after 72 h in the ICU, respectively. Results. During the SARS period in the ICU, there was an increase in the rate of isolation of MRSA and Stenotrophomonas and Candida species but a disappearance of Pseudomonas and Klebsiella species. The MRSA acquisition rate was also increased: it was 3.53% (3.53 cases per 100 admissions) during the pre-SARS period, 25.30% during the SARS period, and 2.21% during the post-SARS period (P < .001). The VAP rate was high, at 36.5 episodes per 1000 ventilator-days, and 47% of episodes were caused by MRSA. Conclusions. A SARS outbreak in the ICU led to changes in the pathogen pattern and the MRSA acquisition rate. The data suggest that MRSA cross-transmission may be increased if gloves and gowns are worn all the time.published_or_final_versio

Validation and reliability of the Physical Activity Scale for the Elderly in Chinese population

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Sequential introduction of single room isolation and hand hygiene campaign in the control of methicillin-resistant Staphylococcus aureus in intensive care unit

<p>Abstract</p> <p>Background</p> <p>After renovation of the adult intensive care unit (ICU) with installation of ten single rooms, an enhanced infection control program was conducted to control the spread of methicillin-resistant <it>Staphylococcus aureus </it>(MRSA) in our hospital.</p> <p>Methods</p> <p>Since the ICU renovation, all patients colonized or infected with MRSA were nursed in single rooms with contact precautions. The incidence of MRSA infection in the ICU was monitored during 3 different phases: the baseline period (phase 1); after ICU renovation (phase 2) and after implementation of a hand hygiene campaign with alcohol-based hand rub (phase 3). Patients infected with extended spectrum beta-lactamase (ESBL)-producing <it>Escherichia coli </it>and <it>Klebsiella species </it>were chosen as controls because they were managed in open cubicles with standard precautions.</p> <p>Results</p> <p>Without a major change in bed occupancy rate, nursing workforce, or the protocol of environmental cleansing throughout the study period, a stepwise reduction in ICU onset nonbacteraemic MRSA infection was observed: from 3.54 (phase 1) to 2.26 (phase 2, p = 0.042) and 1.02 (phase 3, p = 0.006) per 1000-patient-days. ICU onset bacteraemic MRSA infection was significantly reduced from 1.94 (phase 1) to 0.9 (phase 2, p = 0.005) and 0.28 (phase 3, p = 0.021) per 1000-patient-days. Infection due to ESBL-producing organisms did not show a corresponding reduction. The usage density of broad-spectrum antibiotics and fluoroquinolones increased from phase 1 to 3. However a significant trend improvement of ICU onset MRSA infection by segmented regression analysis can only be demonstrated when comparison was made before and after the severe acute respiratory syndrome (SARS) epidemic. This suggests that the deaths of fellow healthcare workers from an occupational acquired infection had an overwhelming effect on their compliance with infection control measures.</p> <p>Conclusion</p> <p>Provision of single room isolation facilities and promotion of hand hygiene practice are important. However compliance with infection control measures relies largely on a personal commitment, which may increase when personal safety is threatened.</p

Do Neutrophils Play a Role in Establishing Liver Abscesses and Distant Metastases Caused by Klebsiella pneumoniae?

Serotype K1 Klebsiella pneumoniae is a major cause of liver abscesses and endophthalmitis. This study was designed to identify the role of neutrophils in the development of distant metastatic complications that were caused by serotype K1 K. pneumoniae. An in vitro cellular model was used to assess serum resistance and neutrophil-mediated killing. BALB/c mice were injected with neutrophils containing phagocytosed K. pneumoniae. Serotype K1 K. pneumoniae was significantly more resistant to serum killing, neutrophil-mediated phagocytosis and intra-cellular killing than non-K1 isolates (p<0.01). Electron microscopic examination had similar findings as in the bioassay findings. Intraperitoneal injection of neutrophils containing phagocytosed serotype K1 K. pneumoniae led to abscess formation in multiple sites including the subcutaneous tissue, lung, and liver, whereas no abscess formation was observed in mice injected with non-K1 isolates. The resistance of serotype K1 K. pneumoniae to complement- and neutrophil-mediated intracellular killing results in the dissemination of K. pneumoniae via the bloodstream. Escape from neutrophil intracellular killing may contribute to the dissemination and establishment of distant metastases. Thus, neutrophils play a role as a vehicle for helping K. pneumoniae and contributing to the establishment of liver abscess and distant metastatic complications

Production of phi mesons at mid-rapidity in sqrt(s_NN) = 200 GeV Au+Au collisions at RHIC

We present the first results of meson production in the K^+K^- decay channel from Au+Au collisions at sqrt(s_NN) = 200 GeV as measured at mid-rapidity by the PHENIX detector at RHIC. Precision resonance centroid and width values are extracted as a function of collision centrality. No significant variation from the PDG accepted values is observed. The transverse mass spectra are fitted with a linear exponential function for which the derived inverse slope parameter is seen to be constant as a function of centrality. These data are also fitted by a hydrodynamic model with the result that the freeze-out temperature and the expansion velocity values are consistent with the values previously derived from fitting single hadron inclusive data. As a function of transverse momentum the collisions scaled peripheral.to.central yield ratio RCP for the is comparable to that of pions rather than that of protons. This result lends support to theoretical models which distinguish between baryons and mesons instead of particle mass for explaining the anomalous proton yield.Comment: 326 authors, 24 pages text, 23 figures, 6 tables, RevTeX 4. To be submitted to Physical Review C as a regular article. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm