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1.
Clin Radiol ; 78(9): 671-678, 2023 09.
Article in English | MEDLINE | ID: mdl-37336673

ABSTRACT

AIM: To enhance ultrasound teaching delivery to radiology trainees using a simulation course matched to the 2021 Royal College of Radiologists (RCR) curriculum. MATERIAL AND METHODS: An ultrasound simulation training course was designed for specialty trainees (ST) 1 in radiology, which was based on the 2021 RCR curriculum and covered the top ultrasound training priorities. The course was piloted initially on two occasions in a 1-day format to the August 2021 and the March 2022 ST1 intake trainees. Based on the feedback, a comprehensive 4-day course was developed and delivered between October and December 2022 for the August 2022 ST1 intake, funded by Health Education England. The outcomes measured were subjective trainee feedback using numerical scores and free text. RESULTS: All King's College Hospital NHS Foundation Trust radiology ST1 trainees from the August 2021 to the August 2022 intake participated in ultrasound simulation training. The training matched the RCR curriculum and increased the trainees' confidence and competency in medical ultrasound. CONCLUSIONS: Ultrasound simulation training can be successfully delivered to ST1 trainees to match the 2021 RCR curriculum and enhance training in medical ultrasound for radiologists.


Subject(s)
Radiology , Simulation Training , Humans , London , Radiology/education , Curriculum , Radiologists , Clinical Competence
2.
Hong Kong Med J ; 29(2): 105-111, 2023 04.
Article in English | MEDLINE | ID: mdl-36990676

ABSTRACT

INTRODUCTION: This study aims to determine the outcomes of stereotactic body radiotherapy (SBRT) for liver metastases in patients not eligible for surgery. METHODS: This study included 31 consecutive patients with unresectable liver metastases who received SBRT between January 2012 and December 2017; 22 patients had primary colorectal cancer and nine patients had primary non-colorectal cancer. Treatments ranged from 24 Gy to 48 Gy in 3 to 6 fractions over 1 to 2 weeks. Survival, response rates, toxicities, clinical characteristics, and dosimetric parameters were evaluated. Multivariate analysis was performed to identify significant prognostic factors for survival. RESULTS: Among these 31 patients, 65% had received at least one prior regimen of systemic therapy for metastatic disease, whereas 29% had received chemotherapy for disease progression or immediately after SBRT. The median follow-up interval was 18.9 months; actuarial in-field local control rates at 1, 2, and 3 years after SBRT were 94%, 55%, and 42%, respectively. The median survival duration was 32.9 months; 1-year, 2-year, and 3-year actuarial survival rates were 89.6%, 57.1%, and 46.2%, respectively. The median time to progression was 10.9 months. Stereotactic body radiotherapy was well-tolerated, with grade 1 toxicities of fatigue (19%) and nausea (10%). Patients who received post-SBRT chemotherapy had significant longer overall survival (P=0.039 for all patients and P=0.001 for patients with primary colorectal cancer). CONCLUSION: Stereotactic body radiotherapy can be safely administered to patients with unresectable liver metastases, and it may delay the need for chemotherapy. This treatment should be considered for selected patients with unresectable liver metastases.


Subject(s)
Liver Neoplasms , Radiosurgery , Humans , Radiosurgery/adverse effects , Prognosis , Liver Neoplasms/radiotherapy , Liver Neoplasms/pathology , Retrospective Studies
3.
Environ Res ; 223: 115422, 2023 04 15.
Article in English | MEDLINE | ID: mdl-36738768

ABSTRACT

The study addresses the effects of generalization descriptions on risk perceptions. In a 1-factorial online experiment, 629 participants were randomly allocated to one of three groups. Group G1 received an excerpt of an original press release from the International Agency for Research on Cancer (IARC) regarding mobile phones and cancer, classifying RF EMF as possibly carcinogenic to humans. Group G2 received an additional explanatory text module, and Group G3 received a rewritten text, with both G2 and G3 highlighting that the possible cancer risk only refers to mobile phones. Risk perceptions regarding cell phones and related personal devices, base stations, and high voltage power lines were used as dependent variables measured before and after text reading. Further, the degree to which participants generalized from cell phone-related to other RF EMF exposures was assessed to determine whether this was predictive of their post-text risk perceptions. Regarding risk perceptions, no differences between the three groups were observed after reading the presented texts. Instead, all three experimental groups indicated increased risk perceptions for all electromagnetic field sources. However, we found significant differences according to the prevailing risk generalization belief. Respondents expressing a strong risk generalization belief showed significantly higher risk perceptions for all tested EMF sources (except mobile phones) than subjects with a weak risk generalization belief.


Subject(s)
Cell Phone , Frailty , Humans , Radio Waves , Electromagnetic Fields , Perception
4.
Phys Med ; 95: 73-82, 2022 Mar.
Article in English | MEDLINE | ID: mdl-35134648

ABSTRACT

BACKGROUND: Planning radiosurgery to multiple intracranial metastases is complex and shows large variability in dosimetric quality among planners and treatment planning systems (TPS). This project aimed to determine whether autoplanning using the Muliple Brain Mets (AutoMBM) software can improve plan quality and reduce inter-planner variability by crowdsourcing results from prior international planning study. METHODS: Twenty-four institutions autoplanned with AutoMBM on a five metastases case from a prior international planning competition from which population statistics (means and variances) of 23 dosimetric metrics and resulting composite plan score (maximum score = 150) of other TPS (Eclipse, Monaco, RayStation, iPlan, GammaPlan, MultiPlan) were crowdsourced. Plan results of AutoMBM and each of the other TPS were compared using two sample t-tests for means and Levene's tests for variances. Plan quality of AutoMBM was correlated with the planner' experience and compared between academic and non-academic centers. RESULTS: AutoMBM produced plans with comparable composite plan score to GammaPlan, MultiPlan, Eclipse and iPlan (127.6 vs. 131.7 vs. 127.3 vs. 127.3 and 126.7; all p > 0.05) and superior to Monaco and RayStation (118.3 and 108.6; both p < 0.05). Inter-planner variability of overall plan quality was lowest for AutoMBM among all TPS (all p < 0.05). AutoMBM's plan quality did not differ between academic and non-academic centers and uncorrelated with planning experience (all p > 0.05). CONCLUSIONS: By plan crowdsourcing prior international plan challenge, AutoMBM produces high and consistent plan quality independent of the planning experience and the institution that is crucial to addressing the technical bottleneck of SRS to intracranial metastases.


Subject(s)
Brain Neoplasms , Crowdsourcing , Radiosurgery , Radiotherapy, Intensity-Modulated , Automation , Brain Neoplasms/secondary , Humans , Internet , Radiosurgery/methods , Radiotherapy Dosage , Radiotherapy Planning, Computer-Assisted/methods , Radiotherapy, Intensity-Modulated/methods
6.
Mol Psychiatry ; 23(5): 1169-1180, 2018 05.
Article in English | MEDLINE | ID: mdl-29155802

ABSTRACT

Anorexia nervosa (AN) is a complex neuropsychiatric disorder presenting with dangerously low body weight, and a deep and persistent fear of gaining weight. To date, only one genome-wide significant locus associated with AN has been identified. We performed an exome-chip based genome-wide association studies (GWAS) in 2158 cases from nine populations of European origin and 15 485 ancestrally matched controls. Unlike previous studies, this GWAS also probed association in low-frequency and rare variants. Sixteen independent variants were taken forward for in silico and de novo replication (11 common and 5 rare). No findings reached genome-wide significance. Two notable common variants were identified: rs10791286, an intronic variant in OPCML (P=9.89 × 10-6), and rs7700147, an intergenic variant (P=2.93 × 10-5). No low-frequency variant associations were identified at genome-wide significance, although the study was well-powered to detect low-frequency variants with large effect sizes, suggesting that there may be no AN loci in this genomic search space with large effect sizes.


Subject(s)
Anorexia Nervosa/genetics , Cell Adhesion Molecules/genetics , Exome/genetics , Family , Female , GPI-Linked Proteins/genetics , Genetic Predisposition to Disease/genetics , Genetic Variation/genetics , Genome-Wide Association Study , Genotype , Humans , Introns/genetics , Male , Phenotype , Polymorphism, Single Nucleotide/genetics , White People/genetics
7.
Hong Kong Med J ; 23(4): 387-94, 2017 Aug.
Article in English | MEDLINE | ID: mdl-28649094

ABSTRACT

Pregnancy-associated breast cancer is the most common malignancy during pregnancy with an expected rise in incidence. The belief in the need for termination of pregnancy and that chemotherapy is contra-indicated during pregnancy is challenged by recent evidence. Patients can consider breast-conserving surgery and sentinel lymph node biopsy with acceptably low fetal risk from radiation exposure. A range of chemotherapeutics is possible in the second trimester in terms of drug class and frequency. Hormonal therapy and monoclonal antibody therapy are contra-indicated during pregnancy and lactation. Fetal outcome after in-utero exposure to chemotherapy appears similar to that in a non-pregnant population. Future pregnancy, in most situations, does not appear to be contra-indicated but a multidisciplinary and patient-centred approach is recommended. Fertility preservation techniques are also being developed with reported success and consequent pregnancies.


Subject(s)
Breast Neoplasms/therapy , Disease Management , Pregnancy Complications, Neoplastic/therapy , Adult , Antineoplastic Combined Chemotherapy Protocols/adverse effects , Female , Humans , Infant, Newborn , Mastectomy, Segmental/adverse effects , Maternal Exposure/adverse effects , Pregnancy , Sentinel Lymph Node Biopsy/adverse effects
8.
Pediatr Blood Cancer ; 63(8): 1477-9, 2016 08.
Article in English | MEDLINE | ID: mdl-27100283

ABSTRACT

A 7-year-old male with Stage 4 neuroblastoma was treated with chemotherapy and autologous hematopoietic stem cell transplantation (HSCT), resulting in partial response with residual bone and marrow disease. He proceeded to haploidentical-HSCT with his mother as donor and achieved remission. The patient developed marrow relapse 2 years after haploidentical-HSCT with cytopenia and dropping donor chimerism. Donor lymphocyte infusion (DLI) using mother's whole blood was given resulting in clearance of marrow disease, resolution of cytopenia, and full donor chimerism. This is the first report of successful treatment for neuroblastoma relapse after haploidentical-HSCT using DLI alone, supporting the role of adoptive cell therapy post-HSCT in neuroblastoma.


Subject(s)
Antineoplastic Agents/therapeutic use , Hematopoietic Stem Cell Transplantation/methods , Immunotherapy, Adoptive/methods , Neoplasm Recurrence, Local/therapy , Neuroblastoma/therapy , Child , Humans , Male , Transplantation, Homologous
9.
Clin Otolaryngol ; 41(6): 782-787, 2016 Dec.
Article in English | MEDLINE | ID: mdl-26990969

ABSTRACT

BACKGROUND: Chronic rhinosinusitis (CRS) is a prevalent chronic inflammatory disease. The basis of a clinical diagnosis of CRS for primary care physicians (PCPs) is based upon the recognition of a symptom constellation that manifests with the disease. However, because the symptomatology of CRS may overlap with other diagnoses, the referral of patient to the most appropriate specialist may not always occur, leading to further delays in evaluation and treatment. METHODS: Given the emphasis on improving the value of health care in Canada, a decision tree model was designed to evaluate whether an upfront computed tomography (CT) scan of the paranasal sinuses ordered by the PCP for a suspected case of CRS would be more cost-effective when compared to symptom-based specialist referral practice. RESULTS: The CT-based strategy resulted in the patient arriving at the most appropriate specialist 95% (±5%) of the time while the symptom-based referral strategy resulted in the patient arriving at the correct specialist 77% (±18%) of the time. The incremental cost effectiveness ratio (ICER) for the CT-based strategy was $1522 per patient arriving at the correct specialist. CONCLUSION: These results suggest that PCPs can improve the effectiveness of their referrals for CRS by utilising an upfront CT referral strategy. However, it would create an additional cost of approximately $1500 per patient referred. Given these findings, the potential clinical benefits of using an upfront CT scan in the Canadian primary care setting should be further studied to determine the value of the additional money spent to improve the effectiveness of CRS referral.


Subject(s)
Primary Health Care , Referral and Consultation/economics , Rhinitis/diagnostic imaging , Sinusitis/diagnostic imaging , Tomography, X-Ray Computed/economics , Canada , Chronic Disease , Cost-Benefit Analysis , Decision Trees , Humans
10.
J Autism Dev Disord ; 46(6): 2138-2147, 2016 06.
Article in English | MEDLINE | ID: mdl-26899725

ABSTRACT

Diffusion tensor imaging studies show white matter (WM) abnormalities in children with autism spectrum disorder (ASD). However, investigations are often limited by small samples, particularly problematic given the heterogeneity of ASD. We explored WM using DTI in a large sample of 130 children and adolescents (7-15 years) with and without ASD, whether age-related changes differed between ASD and control groups, and the relation between DTI measures and ASD symptomatology. Reduced fractional anisotropy and axial diffusivity were observed in ASD in numerous WM tracts, including the corpus callosum and thalamocortical fibres-tracts crucial for interhemispheric connectivity and higher order information processing. Widespread WM compromise in ASD is consistent with the view that ASD is a disorder of generalized complex information processing.


Subject(s)
Autism Spectrum Disorder/diagnostic imaging , White Matter/diagnostic imaging , Adolescent , Anisotropy , Brain/diagnostic imaging , Child , Corpus Callosum/diagnostic imaging , Diffusion Tensor Imaging/methods , Female , Humans , Male
11.
Neuroimage Clin ; 8: 170-9, 2015.
Article in English | MEDLINE | ID: mdl-26106541

ABSTRACT

Autism Spectrum Disorder (ASD) is a clinically diagnosed, heterogeneous, neurodevelopmental condition, whose underlying causes have yet to be fully determined. A variety of studies have investigated either cortical, subcortical, or cerebellar anatomy in ASD, but none have conducted a complete examination of all neuroanatomical parameters on a single, large cohort. The current study provides a comprehensive examination of brain development of children with ASD between the ages of 4 and 18 years who are carefully matched for age and sex with typically developing controls at a ratio of one-to-two. Two hundred and ten magnetic resonance images were examined from 138 Control (116 males and 22 females) and 72 participants with ASD (61 males and 11 females). Cortical segmentation into 78 brain-regions and 81,924 vertices was conducted with CIVET which facilitated a region-of-interest- (ROI-) and vertex-based analysis, respectively. Volumes for the cerebellum, hippocampus, striatum, pallidum, and thalamus and many associated subregions were derived using the MAGeT Brain algorithm. The study reveals cortical, subcortical and cerebellar differences between ASD and Control group participants. Diagnosis, diagnosis-by-age, and diagnosis-by-sex interaction effects were found to significantly impact total brain volume but not total surface area or mean cortical thickness of the ASD participants. Localized (vertex-based) analysis of cortical thickness revealed no significant group differences, even when age, age-range, and sex were used as covariates. Nonetheless, the region-based cortical thickness analysis did reveal regional changes in the left orbitofrontal cortex and left posterior cingulate gyrus, both of which showed reduced age-related cortical thinning in ASD. Our finding of region-based differences without significant vertex-based results likely indicates non-focal effects spanning the entirety of these regions. The hippocampi, thalamus, and globus pallidus, were smaller in volume relative to total cerebrum in the ASD participants. Various sub-structures showed an interaction of diagnosis-by-age, diagnosis-by-sex, and diagnosis-by-age-range, in the case where age was divided into childhood (age < 12) and adolescence (12 < age < 18). This is the most comprehensive imaging-based neuro-anatomical pediatric and adolescent ASD study to date. These data highlight the neurodevelopmental differences between typically developing children and those with ASD, and support aspects of the hypothesis of abnormal neuro-developmental trajectory of the brain in ASD.


Subject(s)
Autism Spectrum Disorder/pathology , Cerebellum/growth & development , Cerebral Cortex/growth & development , Globus Pallidus/growth & development , Human Development/physiology , Magnetic Resonance Imaging/methods , Thalamus/growth & development , Adolescent , Cerebellum/pathology , Cerebral Cortex/pathology , Child , Child, Preschool , Female , Globus Pallidus/pathology , Humans , Male , Thalamus/pathology
12.
Transl Psychiatry ; 5: e494, 2015 Jan 13.
Article in English | MEDLINE | ID: mdl-25585166

ABSTRACT

There is an urgent need for the identification of Alzheimer's disease (AD) biomarkers. Studies have now suggested the promising use of associations with blood metabolites as functional intermediate phenotypes in biomedical and pharmaceutical research. The aim of this study was to use lipidomics to identify a battery of plasma metabolite molecules that could predict AD patients from controls. We performed a comprehensive untargeted lipidomic analysis, using ultra-performance liquid chromatography/mass spectrometry on plasma samples from 35 AD patients, 40 elderly controls and 48 individuals with mild cognitive impairment (MCI) and used multivariate analysis methods to identify metabolites associated with AD status. A combination of 10 metabolites could discriminate AD patients from controls with 79.2% accuracy (81.8% sensitivity, 76.9% specificity and an area under curve of 0.792) in a novel test set. Six of the metabolites were identified as long chain cholesteryl esters (ChEs) and were reduced in AD (ChE 32:0, odds ratio (OR)=0.237, 95% confidence interval (CI)=0.10-0.48, P=4.19E-04; ChE 34:0, OR=0.152, 95% CI=0.05-0.37, P=2.90E-04; ChE 34:6, OR=0.126, 95% CI=0.03-0.35, P=5.40E-04; ChE 32:4, OR=0.056, 95% CI=0.01-0.24, P=6.56E-04 and ChE 33:6, OR=0.205, 95% CI=0.06-0.50, P=2.21E-03, per (log2) metabolite unit). The levels of these metabolites followed the trend control>MCI>AD. We, additionally, found no association between cholesterol, the precursor of ChE and AD. This study identified new ChE molecules, involved in cholesterol metabolism, implicated in AD, which may help identify new therapeutic targets; although, these findings need to be replicated in larger well-phenotyped cohorts.


Subject(s)
Alzheimer Disease/blood , Cholesterol Esters/blood , Cognitive Dysfunction/blood , Aged , Aged, 80 and over , Alzheimer Disease/diagnosis , Biomarkers/blood , Case-Control Studies , Chromatography, Liquid , Cognitive Dysfunction/diagnosis , Female , Humans , Male , Mass Spectrometry , Multivariate Analysis , Sensitivity and Specificity
14.
Ann Surg Oncol ; 21(4): 1246-53, 2014 Apr.
Article in English | MEDLINE | ID: mdl-24337541

ABSTRACT

BACKGROUND: Male breast cancer (MBC) is uncommon. As a result, there is limited availability of studies and reviews and even fewer reports from Asia. This is the largest population-based study to compare Chinese MBC patients with female patients during a 10-year period in Hong Kong, Southern China. METHODS: A retrospective review of medical records of 132 male and 8,118 female breast cancer patients between year 1997 and 2006 in Hong Kong was performed. Each MBC patient was matched with three female breast cancer patients for further analysis. Different characteristics, overall, breast-cancer specific, and disease-free survivals (DFS) were compared. RESULTS: Mean age at diagnosis of male and female patients was 64.5 and 52.7 years respectively. Male patients showed lower histological grade, overall stage, smaller tumor size, and more positive sensitivity in hormone receptors. They were more likely to die of causes other than breast cancer. Matched analysis found that the 5-year overall survival (OS), breast-cancer-specific mortality, and DFS for male and female patients were 78.7, 90.5, 90.5, and 77.9, 86.4, and 81.4 % respectively. Male patients had poorer OS at early overall stage but better breast-cancer-specific mortality rates at any age (p < 0.01). Male patients had a significant risk of dying due to any cause in the presence of distant relapse and had less risk of dying when tumor was ER-positive and HER2-positive. CONCLUSIONS: Chinese male breast cancer patients tend to have poorer OS but better breast-cancer-specific survival compared with their female counterparts.


Subject(s)
Breast Neoplasms/epidemiology , Carcinoma, Ductal, Breast/epidemiology , Carcinoma, Intraductal, Noninfiltrating/epidemiology , Adult , Aged , Aged, 80 and over , Breast Neoplasms/mortality , Breast Neoplasms/pathology , Carcinoma, Ductal, Breast/mortality , Carcinoma, Ductal, Breast/pathology , Carcinoma, Intraductal, Noninfiltrating/mortality , Carcinoma, Intraductal, Noninfiltrating/pathology , Female , Follow-Up Studies , Hong Kong/epidemiology , Humans , Incidence , Male , Middle Aged , Neoplasm Grading , Neoplasm Invasiveness , Neoplasm Staging , Prognosis , Retrospective Studies , Survival Rate , Time Factors
15.
Genes Immun ; 15(2): 88-94, 2014 Mar.
Article in English | MEDLINE | ID: mdl-24335707

ABSTRACT

The IFNL3 genotype predicts the clearance of hepatitis C virus (HCV), spontaneously and with interferon (IFN)-based therapy. The responder genotype is associated with lower expression of interferon stimulated genes (ISGs) in liver biopsies from chronic hepatitis C patients. However, ISGs represent many interacting molecular pathways, and we hypothesised that the IFNL3 genotype may produce a characteristic pattern of ISG expression explaining the effect of genotype on viral clearance. For the first time, we identified an association between a cluster of ISGs, the metallothioneins (MTs) and IFNL3 genotype. Importantly, MTs were significantly upregulated (in contrast to most other ISGs) in HCV-infected liver biopsies of rs8099917 responders. An association between lower fibrosis scores and higher MT levels was demonstrated underlying clinical relevance of this association. As expected, overall ISGs were significantly downregulated in biopsies from subjects with the IFNL3 rs8099917 responder genotype (P=2.38 × 10(-7)). Peripheral blood analysis revealed paradoxical and not previously described findings with upregulation of ISGs seen in the responder genotype (P=1.00 × 10(-4)). The higher MT expression in responders may contribute to their improved viral clearance and MT-inducing agents may be useful adjuncts to therapy for HCV. Upregulation of immune cell ISGs in responders may also contribute to the IFNL3 genotype effect.


Subject(s)
Hepatitis C, Chronic/drug therapy , Interleukins/genetics , Metallothionein/biosynthesis , Viral Load/genetics , Genotype , Hepacivirus , Humans , Interferon Regulatory Factors/genetics , Interferon-alpha/therapeutic use , Interferons , Liver/pathology , Liver/virology , Liver Cirrhosis/genetics , Polyethylene Glycols/therapeutic use , Polymorphism, Single Nucleotide , Recombinant Proteins/therapeutic use , Ribavirin/therapeutic use , Treatment Outcome , Up-Regulation
16.
Hong Kong Med J ; 19(5): 393-9, 2013 Oct.
Article in English | MEDLINE | ID: mdl-23878201

ABSTRACT

OBJECTIVES: To evaluate the efficacy of a birth ball exercise programme conducted by physiotherapists on pain relief, psychological care, and facilitation of the labour process at a labour ward in a regional hospital. DESIGN: Case series with before-after comparisons. SETTING: Kwong Wah Hospital, Hong Kong. PARTICIPANTS: Chinese women admitted to the labour ward for spontaneous vaginal delivery between April and August 2012 were recruited. Physiotherapists taught birth ball exercises in groups or individually for 30 minutes. Labour pain intensity, back pain intensity, frequency of labour pain, stress and anxiety levels, and subjective pressure level over the lower abdomen were captured before and after birth ball exercises. Most of the parameters were measured using self-reported visual analogue scales. After the exercise session, physiotherapists measured the women's satisfaction level. Midwives recorded pethidine usage. RESULTS: A total of 203 pregnant women participated in this programme; 181 were in the latent phase group, whereas 22 were categorised into the no-labour-pain group. In both groups, there were statistically and clinically significant differences in back pain level, stress and anxiety levels, as well as pressure level over the lower abdomen before and after the exercise (P<0.05). In the latent phase group, significant decreases in labour pain and frequency of labour pain were demonstrated. Mean satisfaction scores were high, with visual analogue scale scores higher than 8.2 in both groups. Pethidine usage showed a further decreasing trend (6.4%) compared with the past 2 years. CONCLUSION: Birth ball exercise could be an alternative means of relieving back pain and labour pain in the labour ward, and could decrease pethidine consumption in labouring women.


Subject(s)
Exercise Therapy/methods , Labor Pain/therapy , Labor, Obstetric , Patient Satisfaction , Adult , Analgesics, Opioid/administration & dosage , Anxiety/etiology , Anxiety/therapy , Delivery, Obstetric , Female , Hong Kong , Humans , Meperidine/administration & dosage , Pain Measurement , Pregnancy , Stress, Psychological/etiology , Stress, Psychological/therapy
17.
J Acoust Soc Am ; 133(2): 697-708, 2013 Feb.
Article in English | MEDLINE | ID: mdl-23363089

ABSTRACT

This paper reports a numerical study of the aeroacoustics of merging flow at T-junction. The primary focus is to elucidate the acoustic generation by the flow unsteadiness. The study is conducted by performing direct aeroacoustic simulation approach, which solves the unsteady compressible Navier-Stokes equations and the perfect gas equation of state simultaneously using the conservation element and solution element method. For practical flows, the Reynolds number based on duct width is usually quite high (>10(5)). In order to properly account for the effects of flow turbulence, a large eddy simulation methodology together with a wall modeling derived from the classical logarithm wall law is adopted. The numerical simulations are performed in two dimensions and the acoustic generation physics at different ratios of side-branch to main duct flow velocities VR (=0.5,0.67,1.0,2.0) are studied. Both the levels of unsteady interactions of merging flow structures and the efficiency of acoustic generation are observed to increase with VR. Based on Curle's analogy, the major acoustic source is found to be the fluctuating wall pressure induced by the flow unsteadiness occurred in the downstream branch. A scaling between the wall fluctuating force and the efficiency of the acoustic generation is also derived.


Subject(s)
Acoustics , Models, Theoretical , Sound , Acoustics/instrumentation , Computer Simulation , Equipment Design , Motion , Noise/prevention & control , Numerical Analysis, Computer-Assisted , Pressure , Rheology , Time Factors
18.
Clin Microbiol Infect ; 19(10): 930-5, 2013 Oct.
Article in English | MEDLINE | ID: mdl-23167452

ABSTRACT

While much effort has been made to characterize influenza A pdm09 virus (pH1N1), the flu that was responsible for the fourth influenza pandemic, there is a lack of study on the composition of bacteria that lead to secondary infection. In this study, we recruited pneumonia patients with and without pH1N1 infection and characterized their oropharyngeal microbiota by the unbiased high-throughput sequencing method. While there were no significant differences in common bacterial pneumonia-causative agents (Acinetobacter and Streptococcus species), previously unreported Pseudomonas species equipped with chemotaxis and flagellar assembly genes significantly increased (>20-fold) in the pH1N1-infected group. Bacillus and Ralstonia species that also increased significantly (5-10-fold) were also found to possess similar signaling and motility genes. In contrast, no such genes were found in oral commensal Prevotella, Veillonella and Neisseria species, which decreased significantly, or in either Acinetobacter or 10 out of 21 Streptococcus species, including Streptococcus pneumoniae. Our results support the notion that pH1N1 infection provides a niche for previously unnoticed potential respiratory pathogens that were able to access the lower respiratory tract with weakened immunity.


Subject(s)
Bacteria/genetics , Bacteria/pathogenicity , Coinfection/microbiology , Influenza A Virus, H1N1 Subtype/physiology , Influenza, Human/microbiology , Pneumonia, Bacterial/microbiology , Adolescent , Adult , Aged , Bacteria/classification , Bacteria/isolation & purification , Chemotaxis/genetics , Chemotaxis/physiology , China/epidemiology , Coinfection/epidemiology , Coinfection/virology , Female , Humans , Influenza, Human/epidemiology , Influenza, Human/virology , Male , Microbiota , Middle Aged , Oropharynx/microbiology , Oropharynx/virology , Pneumonia, Bacterial/epidemiology , Pneumonia, Bacterial/virology , Pseudomonas/physiology , Young Adult
19.
J Sex Transm Dis ; 2013: 958967, 2013.
Article in English | MEDLINE | ID: mdl-26316969

ABSTRACT

Background. Community sampling of men having sex with men (MSM) for human immunodeficiency virus (HIV) and sexually transmitted infections prevalence studies poses challenges in view of problems in logistics and the hidden nature of MSM population. Methods. MSM in Hong Kong were recruited through social venues and the Internet. All participants were invited to complete a behavioural questionnaire and submit a urine specimen for HIV, Chlamydia, and gonorrhoea testing. Results. Totally, 994 MSM were recruited. No differences between venue and online-recruited respondents were identified regarding their demographics and infection status. The prevalence of HIV, Chlamydia, and gonorrhoea was 3.6% (95% CI: 2.6-5.0%), 4.7% (95% CI: 3.6-6.2%), and 0.2% (95% CI: 0.1-0.7%), respectively. Of all HIV cases, only 8.3% were aware of the infection; reflecting newly infected MSM were probably overrepresented. Some 58.3% had had HIV test within the past year, and 11.1% had CT/NG coinfection. HIV infection was associated with group sex [aOR: 2.67 (1.03-6.92)], receiving money for anal sex [aOR: 4.63 (1.12-19.18)], and unprotected anal sex with nonregular partners [aOR: 3.047 (1.16-8.01)]. Conclusion. Difference between venue- and online-recruited MSM was observed. A combination of sampling methods is complementary for epidemiology purpose. Overall, risk behaviours practised by undiagnosed HIV-positive MSM remains a cause for concern.

20.
Water Sci Technol ; 65(3): 410-7, 2012.
Article in English | MEDLINE | ID: mdl-22258669

ABSTRACT

Development, population growth and climate change have pressurized water stress in the world. Being an urbanized coastal city, Hong Kong has adopted a dual water supply system since the 1950s for seawater toilet flushing for 80% of its 7 million inhabitants. Despite its success in saving 750,000 m(3)/day of freshwater, the saline sewage (consisting of about 20-30% of seawater) appears to have sacrificed the urban water cycle in terms of wastewater reuse and recycling. Can seawater toilet flushing be applied without affecting the urban water cycle with respect to sustainable water resource management? To address this issue, we examined the entire urban water cycle and developed an innovative water resource management system by integrating freshwater, seawater and reclaimed grey water into a sustainable, low-freshwater demand, low-energy consumption, and low-cost triple water supply (TWS) system. The applicability of this novel system has been demonstrated at the Hong Kong International Airport which reduced 52% of its freshwater demand.


Subject(s)
Airports , Fresh Water/chemistry , Recycling , Seawater/chemistry , Waste Disposal, Fluid/methods , Environment , Hong Kong , Recycling/economics , Recycling/methods , Toilet Facilities
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