Zhilong Chen

Rapid identification of multiple constantly-released contaminant sources in indoor environments with unknown release time

n Abstractn n The sudden release of airborne hazardous contaminants in an indoor environment can potentially lead to severe disasters, such as the spread of toxic gases, fire, and explosion. To prevent and mitigate these disasters it is critical to rapidly and accurately identify the characteristics of the contaminant sources. Although remarkable achievements have been made in identifying a single indoor contaminant source in recent years, the issues related to multiple contaminant sources are still challenging. This study presents a method for identifying the exact locations, emission rates, and release time of multiple indoor contaminant sources simultaneously released at constant rates, by considering sensor thresholds and measurement errors. The method uses a two-stage procedure for rapid source identification. Before the release of contaminants, only a limited number of time-consuming computational fluid dynamics (CFD) simulations need to be conducted. After the release of contaminants, the method can be executed in real-time. Through case studies in a three-dimensional office the method was numerically demonstrated and validated, and the results show that the method is effective and feasible. The effects of sensor threshold, measurement error and total sampling time on the source identification performance were analysed, and the limitations and applicability of the method were also discussed.n n

Assessing urban lifeline systems immediately after seismic disaster based on emergency resilience

Abstract Resilience is an emerging concept for analyzing the dynamic performance of critical infrastructures during the post-disaster recovery process. Although a number of studies examined how to assess long-term resilience (1 year +), very few have investigated short-term resilience (few days to several weeks following a disaster). This study presents the new concept of ‘emergency resilience’ and the framework for assessing this short-term resilience for urban lifeline systems in the emergency recovery stage. This framework can quantify differences in system performance (pre-disaster vs. post-recovery) using the new ‘recovery degree’ feature. It also integrates a new performance response function which is based on network equilibrium theory to assess emergency resilience in both the technical and organisational dimensions. In the case study of the water pipeline network in Lianyungang, China, the results showed that the levels of the recovery budget b and recovery resource r had different effects on emergency resilience R in seismic disaster. Furthermore, it is demonstrated how the concept and its assessment framework can provide a quick reference tool for optimal decision-making under various scenarios. This study also examined the effects of two anti-seismic reconstruction measures, namely meshed expansion and ductile retrofitting, on the expected emergency resilience of the water pipeline network.

Effects Comparison of Different Resilience Enhancing Strategies for Municipal Water Distribution Network: A Multidimensional Approach

Water distribution network (WDN) is critical to the city service, economic rehabilitation, public health, and safety. Reconstructing the WDN to improve its resilience in seismic disaster is an important and ongoing issue. Although a considerable body of research has examined the effects of different reconstruction strategies on seismic resistance, it is still hard for decision-makers to choose optimal resilience enhancing strategy. Taking the pipeline ductile retrofitting and network meshed expansion as demonstration, we proposed a feasible framework to contrast the resilience enhancing effects of two reconstruction strategies—units retrofitting strategy and network optimization strategy—in technical and organizational dimension. We also developed a new performance response function (PRF) which is based on network equilibrium theory to conduct the effects comparison in integrated technical and organizational dimension. Through the case study of municipal WDN in Lianyungang, China, the comparison results were thoroughly shown and the holistic decision-making support was provided.

Electrospinning preparation of timosaponin B-II-Loaded PLLA nanofibers and their antitumor recurrence activities in vivo

Poly(L-lactic)-acid (PLLA) as a drug carrier and a water-soluble drug timosaponin B-II (TB-II) as a model drug were selected to prepare drug-loaded nanofibers by electrospinning. The average diameters of pure PLLA nanofibers and TB-II-loaded nanofibers were 212.5 ± 68.5, 219.7 ± 57.8, 232.8 ± 66.9, and 232.9 ± 97.7 nm, respectively. DSC and XRD results demonstrated that TB-II was well incorporated into the nanofibers in an amorphous state. FI-TR spectroscopy indicated that TB-II had good compatibility with PLLA. In vitro release studies showed that TB-II was rapidly released from the nanofibers within 6 h, followed by a gradual release for long time. In vivo biosafety test revealed no noticeable toxicity of these TB-II nanofibers. The TB-II released from the nanofibers had obvious inhibition effect against human hepatocellular carcinoma SMMC 7721 cells both in vivo and in vitro. It was confirmed that the TB-II-loaded nanofibers were a sustained delivery system which could effectively inhibit the tumor growth and recurrence after surgery.

A fast model for identifying multiple indoor contaminant sources by considering sensor threshold and measurement error

In an emergency where a hazardous contaminant is abruptly released into indoor air, identifying the characteristics of contaminant source promptly and accurately is very important to eliminate source, control contamination and protect people. An identification model is presented in this study for quickly identifying the exact locations and emissions rates of multiple indoor contaminant sources with constant emissions rates and known release time, by considering sensor thresholds and measurement errors. Through case studies in a three-dimensional room, the model was numerically demonstrated and validated, and thorough analyses were made on the effects of the sensor threshold and measurement error on model performance. The results suggest that the model has the potential to obtain accurate results in real-time allowing for high levels of sensor data loss and measurement error. Practical application: The presented identification model is applicable to a wide variety of indoor environments involving multiple continuous contaminant sources, such as the emission of volatile compounds from building materials or furniture, the leakage of toxic or inflammable gases from pipeline or vessels in trace amount. This study will hopefully contribute to developing more realistic source identification techniques with unknown release time and real sensor use.

Characterization of TTN Novex Splicing Variants across Species and the Role of RBM20 in Novex-Specific Exon Splicing

Titin (TTN) is a major disease-causing gene in cardiac muscle. Titin (TTN) contains 363 exons in human encoding various sizes of TTN protein due to alternative splicing regulated mainly by RNA binding motif 20 (RBM20). Three isoforms of TTN protein are produced by mutually exclusive exons 45 (Novex 1), 46 (Novex 2), and 48 (Novex 3). Alternatively splicing in Novex isoforms across species and whether Novex isoforms are associated with heart disease remains completely unknown. Cross-species exon comparison with the mVISTA online tool revealed that exon 45 is more highly conserved across all species than exons 46 and 48. Importantly, a conserved region between exons 47 and 48 across species was revealed for the first time. Reverse transcript polymerase chain reaction (RT-PCR) and DNA sequencing confirmed a new exon named as 48′ in Novex 3. In addition, with primer pairs for Novex 1, a new truncated form preserving introns 44 and 45 was discovered. We discovered that Novex 2 is not expressed in the pig, mouse, and rat with Novex 2 primer pairs. Unexpectedly, three truncated forms were identified. One TTN variant with intron 46 retention is mainly expressed in the human and frog heart, another variant with co-expression of exons 45 and 46 exists predominantly in chicken and frog heart, and a third with retention of introns 45 and 46 is mainly expressed in pig, mouse, rat, and chicken. Using Rbm20 knockout rat heart, we revealed that RBM20 is not a splicing regulator of Novex variants. Furthermore, the expression levels of Novex variants in human hearts with cardiomyopathies suggested that Novexes 2 and 3 could be associated with dilated cardiomyopathy (DCM) and/or arrhythmogenic right ventricular cardiomyopathy (ARVC). Taken together, our study reveals that splicing diversity of Novex exons across species and Novex variants might play a role in cardiomyopathy.

Serum sEPCR Levels Are Elevated in Patients With Alzheimer’s Disease

Blood–brain barrier impairment and endothelial cell dysfunction have both been implicated in the pathogenesis of Alzheimer’s disease (AD). The presence of vascular risk factors is also known to increase the risk of AD. Soluble endothelial protein C receptor (sEPCR) should thus produce procoagulant and proinflammatory effects. Serum sEPCR levels have been found to be associated with several diseases. To date, no reports have been published regarding serum sEPCR levels in AD. In this study, we found that serum sEPCR levels were significantly increased in patients with AD when compared to control participants (P = .0005). There was no significant difference between patients with mild cognitive impairment (MCI) and healthy controls (P = .055) or between patients with AD and MCI (P = .054). Importantly, our results also indicate that the degree of cognitive impairment is significantly correlated with serum sEPCR levels in all patients and healthy controls. These findings suggest that serum sEPCR levels could be a potential candidate for a biomarker panel for AD diagnosis.

The Research on the Impact of the Underground Parking to the Microclimate in Residential Quarter

Currently, more and more residential district have built the underground parking and created more water and green space use the ground. The environment has been improved. This paper analyzed the microclimate of two planning programs use the microclimate fluid dynamics simulation software Envi-met, that one is have been made the underground parking planning, the other one is havent. The results include microclimate parameters air quality parameters (the distribution of CO2) and the outdoor thermal comfort parameters (mean radiant temperature). By comparing the results of the two programs, this paper quantitative analyzed the influence and benefits of the underground parking to the microclimate in residential quarter.