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"Liang, Chang-Wei"
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Impact of kindergarten structures on the dynamics of hand, foot, and mouth disease and the effects of intervention strategies: an agent-based modeling study
Background
Hand, foot, and mouth disease (HFMD) poses an unignorable threat to the health of kindergarten children. Kindergarten structures (i.e., class size and kindergarten size) may influence the transmission dynamics and the effectiveness of non-pharmaceutical interventions (NPIs), but few studies have explored these effects.
Methods
We developed an agent-based network model to study the effects of kindergarten structures on dynamics of HFMD caused by three types of strains (i.e., EV-A71, CVA16, and other EVs). We pursued a systematic review to collect data on HFMD outbreaks to estimate key model parameters. We simulated a series of scenarios to study the effects of NPIs (i.e., isolation of symptomatic individuals, class and family quarantine, and kindergarten closure, organized stepwisely), under different kindergarten sizes (
n
= 180, 360, and 900) and class sizes (
m
= 10, 20, 30, 60, etc.). We further explored alternative interventions combined with vaccination to avoid kindergarten closure during an outbreak.
Results
Overall, we found that the larger the class size, the more cumulative infections and the less effectiveness of NPIs in kindergartens. Stronger NPIs resulted in better effectiveness, and the variations in effectiveness among different class sizes gradually reduced with stronger interventions. Similar patterns were shown in kindergartens with small, medium, and large sizes. NPIs including kindergarten closure, which is implemented in many endemic countries, was a potent epidemic control strategy, capable of reducing cumulative incidence by over 80% for most class sizes in medium-size kindergartens. For EV-A71 infections, a vaccine coverage of 50% was alternative to kindergarten closure, when class size was 60 or less in medium-size kindergartens.
Conclusions
Kindergarten structures, particularly class size, had an important impact on dynamics of HFMD and effectiveness of NPIs within kindergarten. Increasing vaccination coverage may be an alternative to kindergarten closure for control of the disease.
Journal Article
Model-inferred timing and infectious period of the chickenpox outbreak source
Background
In May 2024, a chickenpox outbreak was reported at Xiasha Primary School located in Nanshan District, Shenzhen City, China, with a total of 12 cases identified. Despite thorough on-site investigations, the source of infection remained undetected. The purpose of our study was to infer the timing and duration of the infectious period of the initial case using modeling techniques, thereby deducing the identity of the source.
Methods
We conducted an individual contact survey within the class affected by the epidemic and utilized an agent-based model (ABM) to estimate the key parameters related to the timing of the infectious source’s emergence and the duration of its infectiousness. The point estimates derived from the ABM served as prior information for a subsequent Bayesian analysis, which in turn provided the posterior distribution for these parameters.
Results
Our models suggested the infection source entered the classroom around April 24th (95% credible interval: April 22nd to April 26th), with an infectious period of approximately two days. Based on these findings, we should aim to detect students who may have been absent due to atypical chickenpox symptoms during this period and closely examine teachers who were present for two consecutive days for any indication of potential infection.
Conclusion
This study demonstrates the efficacy of combining contact surveys with mathematical modeling for outbreak source tracing, offering a novel approach to supplement field epidemiological surveys.
Clinical trial number
Not applicable.
Journal Article
Use of Digital Image Correlation Method to Measure Bio-Tissue Deformation
Traditionally, strain gauge, extensometer, and reflection tracking markers have been used to measure the deformation of materials under loading. However, the anisotropy and inhomogeneity of most biological materials restricted the accessibility of the real strain field. Compared to the video extensometer, digital image correlation has the advantage of providing full-field displacement as well as strain information. In this study, a digital image correlation method (DIC) measurement system was employed for chicken breast bio-tissue deformation measurement. To increase the contrast for better correlation, a mixture of ground black pepper and white sesame was sprayed on the surface of samples. The first step was to correct the distorted image caused by the lens using the inverse distorted calibration method and then the influence of subset size and correlation criteria, sum of squared differences (SSD), and zero-normalized sum of squared differences (ZNSSD) were investigated experimentally for accurate measurement. Test results of the sample was translated along the horizontal direction from 0 mm to 3 mm, with an increment of 0.1 mm and the measurement result was compared, and the displacement set on the translation stage. The result shows that the error is less than 3%, and accurate measurement can be achieved with proper surface preparation, subset size, correlation criterion, and image correction. Detailed examination of the strain values show that the strain εx is proportional to the displacement of crosshead, but the strain εy indicates the viscoelastic behavior of tested bio-tissue. In addition, the tested bio-tissue’s linear birefringence extracted by a Mueller matrix polarimetry is for comparison and is in good agreement. As noted above, the integration of the optical parameter measurement system and the digital image correlation method is proposed in this paper to analyze the relationship between the strain changes and optical parameters of biological tissue, and thus the relative optic-stress coefficient can be significantly characterized if Young’s modulus of biological tissue is known.
Journal Article
Collared Anastomosis＂ Technique Used in Arch Replacement Combined with Frozen Elephant Trunk Implantation Procedure for Giant Arch and Thoracic Aorta Dilatation
To the Editor： We report two cases of arch replacement combined with frozen elephant trunk implantation procedure using the collared anastomosis technique for giant arch and thoracic aorta dilatation.
Journal Article
Medium oxygen enriched blast furnace with top gas recycling strategy
Top gas recycling oxygen blast furnace（TGR-OBF）process is a promising ironmaking process.The biggest challenge of the TGR-OBF in operation is the dramatic decrease of top gas volume（per ton hot metal）,which once led to hanging-up and shutdowns in practice of the Toulachermet.In order to avoid this weakness,the strategy of medium oxygen blast furnace was presented.The maneuverable zone of the TGR-OBF was determined by the top gas volume,which should not be far from the data of the traditional blast furnace.The deviation of ±12.5% was used,and then the maneuverable blast oxygen content is from 0.30 to 0.47 according to the calculation.The flame temperature and the top gas volume have no much difference compared to those of the traditional blast furnace.The minimum carbon consumption of 357 kg per ton hot metal in the maneuverable zone occurs at the oxygen content of 0.30（fuel saving of 14%）.In the unsteady evolution,the N2 accumulation could approach nearly zero after the recycling reached 6 times.Thus far,some TGR-OBF industrial trials have been carried out in different countries,but the method of medium oxygen enriched TGR-OBF has not been implemented,because the accumulation of N2 was worried about.The presented strategy of medium oxygen enriched TGR-OBF is applicable and the strategy with good operational performance is strongly suggested as a forerunner of the full oxygen blast furnace.
Journal Article
An Anti-Collision Device with Circumferentially Energy Absorption under a Local Impact
A new design of anti-collision device is present in this paper. When the collision occurs, with the deformation movement, the anti-collision device can transfer the collision energy to the non-contact area, store the energy and release after collision, which can not only protect the protected object, but also reduce the damage to the collision-causing object, ensuring the anti-collision device itself can be reusable. As a result, this design of anti-collision device can greatly reduce damages and economic losses caused by the accidental collision.
Journal Article
Medium oxygen enriched blast furnace with top gas recycling strategy
Top gas recycling oxygen blast furnace(TGR-OBF)process is a promising ironmaking process.The biggest challenge of the TGR-OBF in operation is the dramatic decrease of top gas volume(per ton hot metal),which once led to hanging-up and shutdowns in practice of the Toulachermet.In order to avoid this weakness,the strategy of medium oxygen blast furnace was presented.The maneuverable zone of the TGR-OBF was determined by the top gas volume,which should not be far from the data of the traditional blast furnace.The deviation of ±12.5% was used,and then the maneuverable blast oxygen content is from 0.30 to 0.47 according to the calculation.The flame temperature and the top gas volume have no much difference compared to those of the traditional blast furnace.The minimum carbon consumption of 357 kg per ton hot metal in the maneuverable zone occurs at the oxygen content of 0.30(fuel saving of 14%).In the unsteady evolution,the N2 accumulation could approach nearly zero after the recycling reached 6 times.Thus far,some TGR-OBF industrial trials have been carried out in different countries,but the method of medium oxygen enriched TGR-OBF has not been implemented,because the accumulation of N2 was worried about.The presented strategy of medium oxygen enriched TGR-OBF is applicable and the strategy with good operational performance is strongly suggested as a forerunner of the full oxygen blast furnace.
Journal Article
Percent free prostate-specific antigen is effective to predict prostate biopsy outcome in Chinese men with prostate-specific antigen between 10.1 and 20.0 ng ml^-1
Percent free prostatic-specific antigen （%fPSA） has been introduced as a tool to avoid unnecessary biopsies in patients with a serum PSA level of 4.0-10.0 ng ml^-1, however, it remains controversial whether %fPSA is effective in PSA range of 10.1-20.0 ng ml^-1 in both Chinese and Western population. In this study, the diagnostic performance of %fPSA and serum PSA in predicting prostate cancer （PCa） and high-grade PCa （HGPCa） was analyzed in a multi-center biopsy cohort of 5915 consecutive Chinese patients who underwent prostate biopsy in 22 hospitals across China from January 1, 2010 to December 31, 2013. The indication for biopsy was PSA〉4.0 ng ml^-1 or/and suspicious digital rectal examination. Total and free serum PSA determinations were performed by three types of electrochemiluminescence immunoassays with recalibration to the World Health Organization standards. The diagnostics accuracy of PSA, %fPSA and %fPSA in combination with PSA （%fPSA ＋ PSA） was determined by the area under the receivers operating characteristic curve （AUC）. %fPSA was more effective than PSA in men aged ≥60 years old. The AUC was 0.584 and 0.635 in men aged ≥60 years old with a PSA of 4.0-10.0 ng ml^-1 and 10.1-20.0 ng ml^-1, respectively. The AUC of %fPSA was superior to that of PSA in predicting HGPCa in patients ≥60 years old in these two PSA range. Our results indicated that %fPSA is both statistically effective and clinical applicable to predict prostate biopsy outcome in Chinese patients aged ≥60 years old with a PSA of 4.0-10.0 ng ml^-1 and 10.1-20.0 ng ml^-1.
Journal Article