21 research outputs found
Effects of beam-column depth ratio on seismic behaviour of non-seismic detailed reinforced concrete beam-column joints
Four reinforced concrete exterior beam-column joints with open anchorage beam reinforcement, which are manufactured to simulate those in existing reinforced concrete framed buildings, are tested under reversed cyclic loads simulating earthquake excitation. The particular emphasis of this project is given to the effects of the beam-column depth ratio and the stirrup ratio in joints on the shear strength and seismic behaviour of the exterior joints without seismically designed details. The experimental results indicate that the stirrup placed in the beam-column joint cores can effectively improve the shear strength of the joint and enhance the seismic performance, and the shear strength of the joints decreases when the beam-column depth ratio increases. The experimental results are also compared with the results predicted by two non-seismic design codes (Eurocode 2 and HK code 2013) and three codes for seismic design (Eurocode 8, ACI 318-14 and NZS 3101). In general, the current non-seismic design codes and seismic design codes of practice cannot accurately predict the shear strength of the exterior joints with non-seismically designed details. It is shown that neglecting the seismic design of beam-column joints may lead to potential damage of reinforced concrete framed buildings in unexpected moderate or low seismic areas
The photometric observation of the quasi-simultaneous mutual eclipse and occultation between Europa and Ganymede on 22 August 2021
Mutual events (MEs) are eclipses and occultations among planetary natural
satellites. Most of the time, eclipses and occultations occur separately.
However, the same satellite pair will exhibit an eclipse and an occultation
quasi-simultaneously under particular orbital configurations. This kind of rare
event is termed as a quasi-simultaneous mutual event (QSME). During the 2021
campaign of mutual events of jovian satellites, we observed a QSME between
Europa and Ganymede. The present study aims to describe and study the event in
detail. We observed the QSME with a CCD camera attached to a 300-mm telescope
at the Hong Kong Space Museum Sai Kung iObservatory. We obtained the combined
flux of Europa and Ganymede from aperture photometry. A geometric model was
developed to explain the light curve observed. Our results are compared with
theoretical predictions (O-C). We found that our simple geometric model can
explain the QSME fairly accurately, and the QSME light curve is a superposition
of the light curves of an eclipse and an occultation. Notably, the observed
flux drops are within 2.6% of the theoretical predictions. The size of the
event central time O-Cs ranges from -14.4 to 43.2 s. Both O-Cs of flux drop and
timing are comparable to other studies adopting more complicated models. Given
the event rarity, model simplicity and accuracy, we encourage more observations
and analysis on QSMEs to improve Solar System ephemerides.Comment: 23 pages, 5 appendixes, 16 figures, 7 table
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
Distribution of Sesamoid Bones in the Hand—A Study in the Chinese Population
Objective: To report the prevalence and distribution of hand sesamoid bones in Chinese ethnic group and its left-right symmetry.
Methods: A retrospective study involving hand radiographs taken in patients admitted to United Christian Hospital from January 2011 to June 2014. Exclusion criteria included previous hand fracture, inadequate radiological views and those of non-Chinese ethnic group.
Results: A total of 307 hand radiographs (162 left and 145 right; 181 males and 126 females) in 266 patients were reviewed. Bilateral hand radiographs were available in 41 patients. Their mean age (± standard deviation) was 48.8 ± 11.3 years (range, 25–69 years). The total number of sesamoid bones identified was 1,641. Sesamoid bones were found at the first metacarpophalangeal joint (MCPJ) at a rate of 100%, while the prevalence at the second MCPJ, third MCPJ, fourth MCPJ, fifth MCPJ as well as the first interphalangeal joint (IPJ) was 59.0%, 2.93%, 0%, 47.6% and 28.0%, respectively. Bilateral hand radiographs showed 100% symmetrical distribution of sesamoid bones on right and left sides.
Conclusion: This is the first study in Hong Kong to report prevalence of sesamoid bones in the Chinese Population and identify the symmetry of sesamoid bones in bilateral hands. The result revealed that the Chinese ethnic group had a higher prevalence of sesamoid bones at the 2nd and 3rd MCPJ when compared with other ethnic groups. The distribution of sesamoid bones was symmetrical in bilateral hands
Radiomics from Various Tumour Volume Sizes for Prognosis Prediction of Head and Neck Squamous Cell Carcinoma: A Voted Ensemble Machine Learning Approach
Background: Traditionally, cancer prognosis was determined by tumours size, lymph node spread and presence of metastasis (TNM staging). Radiomics of tumour volume has recently been used for prognosis prediction. In the present study, we evaluated the effect of various sizes of tumour volume. A voted ensemble approach with a combination of multiple machine learning algorithms is proposed for prognosis prediction for head and neck squamous cell carcinoma (HNSCC). Methods: A total of 215 HNSCC CT image sets with radiotherapy structure sets were acquired from The Cancer Imaging Archive (TCIA). Six tumour volumes, including gross tumour volume (GTV), diminished GTV, extended GTV, planning target volume (PTV), diminished PTV and extended PTV were delineated. The extracted radiomics features were analysed by decision tree, random forest, extreme boost, support vector machine and generalized linear algorithms. A voted ensemble machine learning (VEML) model that optimizes the above algorithms was used. The receiver operating characteristic area under the curve (ROC-AUC) were used to compare the performance of machine learning methods, including accuracy, sensitivity and specificity. Results: The VEML model demonstrated good prognosis prediction ability for all sizes of tumour volumes with reference to GTV and PTV with high accuracy of up to 88.3%, sensitivity of up to 79.9% and specificity of up to 96.6%. There was no significant difference between the various target volumes for the prognostic prediction of HNSCC patients (chi-square test, p > 0.05). Conclusions: Our study demonstrates that the proposed VEML model can accurately predict the prognosis of HNSCC patients using radiomics features from various tumour volumes
Study protocol for a randomized controlled trial comparing the effectiveness of physical exercise and melatonin supplement on treating sleep disturbance in children with autism spectrum disorders.
BackgroundPrevious study showed that both melatonin supplement and physical exercise intervention could improve sleep quality in children with autism spectrum disorders (ASD) with the increase in endogenous melatonin level. However, none of the studies have directly compared the effectiveness between the two interventions on treating sleep disturbance in children with ASD. Without direct comparison, we do not know which intervention is better. Thus, we designed a study to compare which intervention is more effective to treat sleep disturbance in children with ASD and to examine whether the combination of the two could be the most efficacious. We present a protocol for conducting a randomized controlled trial to compare the effectiveness of physical exercise and melatonin supplement on treating sleep disturbance in children with ASD.Study designThe proposed study will be a four-group randomised control trial (RCT) design, with equal allocation of participants to the three intervention groups and one control group.MethodsAll eligible participants will be randomly allocated to a morning jogging group, a melatonin supplement group, a combination group and a control group. Changes in sleep quality will be monitored through actigraphic assessment and parental sleep logs. Melatonin levels represented by 6-sulfoxymelatonin will be measured from the participants' 24-h and the first morning void urinary samples. All the assessments will be carried out before the intervention (T1), in the mid of the study (5 weeks after the commencement of the study) (T2) and after the 10-week intervention (T3). Level of statistical significance will be set at 5% (i.e. p FindingsThe findings will provide evidence to determine whether physical exercise or melatonin supplement or the combination of interventions is the most effective to treat sleep disturbance in children with ASD
Relationship between peak knee adduction moment and Kellgren and Lawrence grade in patients with medial compartment knee osteoarthritis
Rationale/Objectives: Biomechanically, medial compartment knee osteoarthritis (MCKOA) has been associated with a greater peak knee adduction moment (KAM). Clinically, Kellgren and Lawrence (KL) grading system is a commonly used radiological classification to indicate the severity of MCKOA. Although strong correlation between peak KAM and KL grades in patients with MCKOA has been previously reported, in view of the large minimal detectable differences in the peak KAM, it is very possible that peak KAM may not be sensitive enough to differentiate KL grades. Hence, this study examined the relationship between KAM and KL grade, as well as compared the peak KAM difference across patients with different KL grades. Methods: Twenty five patients with different severity of MCKOA were recruited from the Prince of Wales Hospital. We measured KAM of the affected knee joint using previously established methods. KL grade of the affected knee was rated by a single orthopedic surgeon. Spearman’s rank correlation (rho) was used to examine the relationship between KAM and KL grade. One-way ANOVA was also employed to compare the KAM difference across KL grades. Results: Peak KAM was significantly correlated to KL grade (rho=0.683; p<0.001) Patients with KL grade 4 MCKOA exhibited significant greater peak KAM than patients with less severity (p<0.05). However, peak KAM was similar between patients with KL grade 1-3 (p=0.291). Conclusions: Peak KAM may not be a sensitive surrogate to indicate the KL grade in patients with MCKOA and other measures should be used to monitor the disease progression
CrusTF: a comprehensive resource of transcriptomes for evolutionary and functional studies of crustacean transcription factors
Abstract Background Crustacea, the second largest subphylum of Arthropoda, includes species of major ecological and economic importance, such as crabs, lobsters, crayfishes, shrimps, and barnacles. With the rapid development of crustacean aquaculture and biodiversity loss, understanding the gene regulatory mechanisms of growth, reproduction, and development of crustaceans is crucial to both aquaculture development and biodiversity conservation of this group of organisms. In these biological processes, transcription factors (TFs) play a vital role in regulating gene expression. However, crustacean transcription factors are still largely unknown, because the lack of complete genome sequences of most crustacean species hampers the studies on their transcriptional regulation on a system-wide scale. Thus, the current TF databases derived from genome sequences contain TF information for only a few crustacean species and are insufficient to elucidate the transcriptional diversity of such a large animal group. Results Our database CrusTF ( http://qinlab.sls.cuhk.edu.hk/CrusTF ) provides comprehensive information for evolutionary and functional studies on the crustacean transcriptional regulatory system. CrusTF fills the knowledge gap of transcriptional regulation in crustaceans by exploring publicly available and newly sequenced transcriptomes of 170 crustacean species and identifying 131,941 TFs within 63 TF families. CrusTF features three categories of information: sequence, function, and evolution of crustacean TFs. The database enables searching, browsing and downloading of crustacean TF sequences. CrusTF infers DNA binding motifs of crustacean TFs, thus facilitating the users to predict potential downstream TF targets. The database also presents evolutionary analyses of crustacean TFs, which improve our understanding of the evolution of transcriptional regulatory systems in crustaceans. Conclusions Given the importance of TF information in evolutionary and functional studies on transcriptional regulatory systems of crustaceans, this database will constitute a key resource for the research community of crustacean biology and evolutionary biology. Moreover, CrusTF serves as a model for the construction of TF database derived from transcriptome data. A similar approach could be applied to other groups of organisms, for which transcriptomes are more readily available than genomes
Lessening of porcine epidemic diarrhoea virus susceptibility in piglets after editing of the CMP-N-glycolylneuraminic acid hydroxylase gene with CRISPR/Cas9 to nullify N-glycolylneuraminic acid expression.
The porcine epidemic diarrhoea virus (PEDV) devastates the health of piglets but may not infect piglets whose CMP-N-glycolylneuraminic acid hydroxylase (CMAH) gene is mutated (knockouts, KO) by using CRISPR/Cas9 gene editing techniques. This hypothesis was tested by using KO piglets that were challenged with PEDV. Two single-guide RNAs targeting the CMAH gene and Cas9 mRNA were microinjected into the cytoplasm of newly fertilized eggs. Four live founders generated and proven to be biallelic KO, lacking detectable N-glycolylneuraminic acid (NGNA). The founders were bred, and homozygous offspring were obtained. Two-day-old (in exps. I, n = 6, and III, n = 15) and 3-day-old (in exp. II, n = 9) KO and wild-type (WT, same ages in respective exps.) piglets were inoculated with TCID50 1x103 PEDV and then fed 20 mL of infant formula (in exps. I and II) or sow's colostrum (in exp. III) every 4 hours. In exp. III, the colostrum was offered 6 times and was then replaced with Ringer/5% glucose solution. At 72 hours post-PEDV inoculation (hpi), the animals either deceased or euthanized were necropsied and intestines were sampled. In all 3 experiments, the piglets showed apparent outward clinical manifestations suggesting that infection occurred despite the CMAH KO. In exp. I, all 6 WT piglets and only 1 of 6 KO piglets died at 72 hpi. Histopathology and immunofluorescence staining showed that the villus epithelial cells of WT piglets were severely exfoliated, but only moderate exfoliation and enterocyte vacuolization was observed in KO piglets. In exp. II, delayed clinical symptoms appeared, yet the immunofluorescence staining/histopathologic inspection (I/H) scores of the two groups differed little. In exp. III, the animals exhibited clinical and pathological signs after inoculation similar to those in exp. II. These results suggest that porcine CMAH KO with nullified NGNA expression are not immune to PEDV but that this KO may lessen the severity of the infection and delay its occurrence