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Various variants of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been emerging and circulating in different parts of the world. Millions of vaccine doses have been administered globally, which reduces the morbidity and mortality of coronavirus disease-2019 efficiently. Here, we assess the immune responses of individuals after two shots of BBIBP-CorV or CoronaVac inactivated vaccine. We measured neutralizing antibody responses after the second vaccination by using authentic SARS-CoV-2 and its viral variants. All the serum samples efficiently neutralized SARS-CoV-2 wild-type lineage, in contrast, a part of serum samples failed to neutralize Alpha, Beta, Gamma, Delta, or Eta lineages, and only several serum samples were able to neutralize Omicron lineage virus strains (BA.1 and BA.2) with low neutralization titer. As compared with the neutralization of SARS-CoV-2 wild-type lineage, the neutralization of all other SARS-CoV-2 variant lineages was significantly lower. Considering that all the SARS-CoV-2 mutation viruses challenged the antibody neutralization induced by BBIBP-CorV and CoronaVac, it is necessary to carry out a third booster vaccination to increase the humoral immune response against the SARS-CoV-2 mutation viruses.

The SARS-CoV-2 Delta variant has spread rapidly worldwide. To provide data on its virological profile, we here report the first local transmission of Delta in mainland China. All 167 infections could be traced back to the first index case. Daily sequential PCR testing of quarantined individuals indicated that the viral loads of Delta infections, when they first become PCR-positive, were on average ~1000 times greater compared to lineage A/B infections during the first epidemic wave in China in early 2020, suggesting potentially faster viral replication and greater infectiousness of Delta during early infection. The estimated transmission bottleneck size of the Delta variant was generally narrow, with 1-3 virions in 29 donor-recipient transmission pairs. However, the transmission of minor iSNVs resulted in at least 3 of the 34 substitutions that were identified in the outbreak, highlighting the contribution of intra-host variants to population-level viral diversity during rapid spread., The SARS-CoV-2 Delta variant has spread rapidly worldwide. Here, the authors characterise a single chain of transmission of Delta in China, and find evidence that it is more infectious and replicates faster during early infection compared to early pandemic lineages.

Purpose In the Guidelines for the Prevention and Control of Type 2 Diabetes in China (2017 edition), intensive lifestyle interventions are recommended for preventing the progression of impaired glucose tolerance (IGT) to type 2 diabetes mellitus. Acarbose and metformin can also be considered if intensive lifestyle modification has been ineffective for 6 months. But the effects of intensive lifestyle modification and glucose-lowering drug interventions that work best in the population with IGT are unclear. This network meta-analysis assessed the effectiveness of intensive lifestyle modification, acarbose, and metformin in treating populations with IGT. Methods We systematically searched both Chinese- and English-language databases, including China Knowledge, the Cochrane Library, Embase, PubMed, VIP, and Wanfang, for articles published between database inception and September 2019. Randomized, controlled clinical trials in patients with IGT treated with acarbose, metformin, and intensive lifestyle modification were assessed for eligibility. The data from all included studies were evaluated by 2 reviewers independently in accordance with the Cochrane Handbook for Systematic Reviews of Intervention version 6.0. A network meta-analysis was performed by using R software version 3.6.1. Findings The data from 53 randomized controlled trials were included in the review, with a sample size of 21,208 patients. Compared with the control group, the use of acarbose, metformin, and/or intensive lifestyle modification was associated with reduced rates of progression to diabetes (relative risks [RRs] [95% credible intervals]: acarbose, 0.37 [0.29–0.47]; metformin, 0.39 [0.30–0.50]; intensive lifestyle modification, 0.61 [0.50–0.73]). The surface under the cumulative ranking (SUCRA) value of acarbose was 88.35%, supporting that acarbose was more effective in reducing the rate of progression to diabetes compared with controls. With acarbose, metformin, and intensive lifestyle modification, the rates of achieving a normal glucose level were increased by RR = 2.1, 1.7, and 1.2, respectively when compared with control group. The SUCRA value of acarbose was 99.69%, supporting the optimal effect of acarbose in achieving a normal blood glucose level. Implications In this meta-analysis in patients with IGT, compared with controls, acarbose and metformin were associated with decreased rates of progression to diabetes and increased rates of achieving a normal glucose level. Acarbose use was associated with an increased rate of achieving a normal glucose level, while intensive lifestyle modification was not.

Pneumonia is the leading cause of hospitalization in pediatric patients. Disease severity greatly influences pneumonia progression and adverse health outcomes such as hospital readmission. Hospital readmissions have become a measure of healthcare quality to reduce excess expenditures. The aim of this study was to examine 30-day all-cause readmission rates and evaluate the association between pneumonia severity and readmission among pediatric pneumonia hospitalizations. Using 2018 Nationwide Readmissions Database (NRD), we conducted a cross-sectional study of pediatric hospitalizations for pneumonia. Pneumonia severity was defined by the presence of respiratory failure, sepsis, mechanical ventilation, dependence on long-term supplemental oxygen, and/or respiratory intubation. Outcomes of interest were 30-day all-cause readmission, length of stay, and cost. The rate of 30-day readmission for the total sample was 5.9%, 4.7% for non-severe pneumonia, and 8.7% for severe pneumonia (p

Cell encapsulation has proven to be promising in stem cell therapy. However, there are issues needed to be addressed, including unsatisfied yield, unmet clinically friendly formulation, and unacceptable viability of stem cells after cryopreservation and thawing. We developed a novel biosynsphere technology to encapsulate stem cells in clinically-ready biomaterials with controlled microsphere size. We demonstrated that biosynspheres ensure the bioviability and functionality of adipose-derived stromal cells (ADSCs) encapsulated, as delineated by a series of testing procedures. We further demonstrated that biosynspheres protect ADSCs from the hardness of clinically handling such as cryopreservation, thawing, high-speed centrifugation and syringe/nozzle injection. In a swine full skin defect model, we showed that biosynspheres were integrated to the destined tissues and promoted the repair of injured tissues with an accelerating healing process, less scar tissue formation and normalized deposition of collagen type I and type III, the ratio similar to that found in normal skin. These findings underscore the potential of biosynsphere as an improved biofabrication technology for tissue regeneration in clinical setting.

There is an increasing demand for supporting the adoption of rapid whole-genome sequencing (rWGS) by demonstrating its real-world value. We aimed to assess the cost-effectiveness of rWGS in critically ill pediatric patients with diseases of unknown cause. Data were collected prospectively of patients admitted to the Nicklaus Children's Hospital's intensive care units from March 2018 to September 2020, with rWGS (N = 65). Comparative data were collected in a matched retrospective cohort with standard diagnostic genetic testing. We determined total costs, diagnostic yield (DY), and incremental cost-effectiveness ratio (ICER) adjusted for selection bias and right censoring. Sensitivity analyses explored the robustness of ICER through bootstrapping. rWGS resulted in a diagnosis in 39.8% while standard testing in 13.5% (p = 0.026). rWGS resulted in a mean saving per person of $100,440 (SE = 26,497, p 0.001) and a total of $6.53 M for 65 patients. rWGS in critically ill pediatric patients is cost-effective, cost-saving, shortens diagnostic odyssey, and triples the DY of traditional approaches.

We report the first local transmission of the SARS-CoV-2 Delta variant in mainland China. All 167 infections could be traced back to the first index case. Daily sequential PCR testing of the quarantined subjects indicated that the viral loads of Delta infections, when they first become PCR+, were on average ~1000 times greater compared to A/B lineage infections during initial epidemic wave in China in early 2020, suggesting potentially faster viral replication and greater infectiousness of Delta during early infection. We performed high-quality sequencing on samples from 126 individuals. Reliable epidemiological data meant that, for 111 transmission events, the donor and recipient cases were known. The estimated transmission bottleneck size was 1-3 virions with most minor intra-host single nucleotide variants (iSNVs) failing to transmit to the recipients. However, transmission heterogeneity of SARS-CoV-2 was also observed. The transmission of minor iSNVs resulted in at least 4 of the 30 substitutions identified in the outbreak, highlighting the contribution of intra-host variants to population level viral diversity during rapid spread. Disease control activities, such as the frequency of population testing, quarantine during pre-symptomatic infection, and level of virus genomic surveillance should be adjusted in order to account for the increasing prevalence of the Delta variant worldwide.

SummaryWe report the first local transmission of the SARS-CoV-2 Delta variant in mainland China. All 167 infections could be traced back to the first index case. Daily sequential PCR testing of the quarantined subjects indicated that the viral loads of Delta infections, when they first become PCR+, were on average ∼1000 times greater compared to A/B lineage infections during initial epidemic wave in China in early 2020, suggesting potentially faster viral replication and greater infectiousness of Delta during early infection. We performed high-quality sequencing on samples from 126 individuals. Reliable epidemiological data meant that, for 111 transmission events, the donor and recipient cases were known. The estimated transmission bottleneck size was 1-3 virions with most minor intra-host single nucleotide variants (iSNVs) failing to transmit to the recipients. However, transmission heterogeneity of SARS-CoV-2 was also observed. The transmission of minor iSNVs resulted in at least 4 of the 30 substitutions identified in the outbreak, highlighting the contribution of intra-host variants to population level viral diversity during rapid spread. Disease control activities, such as the frequency of population testing, quarantine during pre-symptomatic infection, and level of virus genomic surveillance should be adjusted in order to account for the increasing prevalence of the Delta variant worldwide.

At the end of 2019, a coronavirus disease 2019 (COVID-19) outbroke in Wuhan, China, and spread to Guizhou province on January of 2020. To acquire the epidemiologic characteristics of COVID-19 in Guizhou, China, we collected data on 162 laboratory-confirmed cases related to COVID-19. We described the demographic characteristics of the cases and estimated the incubation period, serial interval and basic reproduction number. We also presented two representative case studies in Guizhou province -- Case Study 1 was an example of asymptomatic carrier; and Case Study 2 was an example of a large and complex infection chain that involved four different districts spanning three provinces and eight families. With an estimation of 8 days incubation period and 6 days serial interval, our results indicate that there may exist infectiousness during the incubation period for 2019-nCoV. This increases the difficulty of screening or identifying cases related to COVID-19.

Dynamic behavioral parameters are increasingly postulated as alternatives to traditional mortality testing. Behavioral changes can precede mortality endpoints at substantially lower concentrations and are therefore considered as a useful indicator of sub-lethal effects. Despite recent acknowledgement of the importance of sub-lethal behavioral biotests, their implementation is profoundly limited by the lack of appropriate and user-friendly laboratory automation. This work outlines development of a proof-of-concept miniaturized Lab-on-a-Chip (LOC) platform for rapid aquatic toxicity tests based on changes in swimming patterns exhibited by a ubiquitous saltwater crustacean Artemia franciscana (Artoxkit M™) commonly used for marine ecotoxicity testing. In contrast to any conventionally performed end-point analysis based on counting numbers of dead/immobile specimens we performed a fully automated time-resolved video data analysis to dynamically assess the effect of a reference toxicant on selected behavioral parameters. Our proof-of-concept system combined innovative microfluidic device designed to keep free-swimming Artemia sp. nauplii under continuous microperfusion with a miniaturized video acquisition system for automated movement analysis of test specimens. For the majority of chemical stressors tested, behavioral changes were very rapid and observed often from the first few minutes of toxicant exposure. Furthermore, we identified distinct behavioral responses such as hyperactivity and hypoactivity syndromes in response to chemical stressors exposure. Both behavioral syndromes occurred in a concentration- and exposure time-dependent manner. This work provides evidence that sub-lethal, behavioral analysis performed under microperfusion can prospectively provide much more sensitive effect end-points as compared to conventional protocols where mortality is used as the main evaluation criterion. Innovative Lab-on-a-Chip technologies open a brand new alternative for inexpensive and rapid aquatic ecotoxicity protocols.

Purpose: The distribution and vaccination of COVID-19 vaccines to billions of people worldwide will likely be one of the biggest public health undertakings in history. There has been a large focus on identifying processes to safely, efficiently, and effectively vaccinate large populations. We aimed to describe the development and operationalization of a drive-in COVID-19 vaccine site in a parking garage adjacent to outpatient clinics at University of Florida (UF) Health Physicians and how it was informed by the roll-out of SARS-CoV-2 testing and administration of respiratory vaccinations. Design/Methodology/Approach: A technical description and analysis of a drive-in COVID-19 vaccine site. Findings: We incrementally increased the number of vaccines performed per day from 300 in the first 2 weeks to 700 an additional 2 weeks later. By the end of January, we completed nearly 14 000 vaccinations. At this capacity, we estimate the site could performed 5000 vaccinations per week. Practical Implications: This manuscript provides step-by-step guidance how to develop, operationalize, and implement a sustainable drive-in COVID-19 vaccination site. Originality/Value: To our knowledge, this is the first description of a drive-in approach to COVID-19 vaccination. Our findings can help inform other health entities as they develop or expand vaccination efforts that may serve as a template for other sites to adapt.

© 2017 IEEE. Video segmentation research has emerged over the last decade for biomedical image and video processing, especially in biological organism tracking. However, due to the difficulties in generating the video segmentation ground truth, the general lack of segmentation datasets with annotated ground-truth severely limits the evaluation of segmentation algorithms. This paper proposes an efficient and scalable crowdsourced approach to generate video segmentation ground-Truth to facilitate database generation for general biological organism segmentation and tracking algorithm evaluation. To illustrate the proposed approach, an annotated zebrafish larvae video segmentation dataset has been generated and made freely available online. To enable the evaluation of algorithms against a ground-Truth, a set of segmentation evaluation metrics are also presented. The segmentation performance of five leading segmentation algorithms is then evaluated by the metrics on the generated zebrafish video segmentation dataset.

Dimethyl sulfoxide (DMSO) is a universally used aprotic solvent with the ability to permeate biological membranes and thus is commonly used to achieve appropriate biological availability of hydrophobic toxicants. While DMSO as a carrier medium has a reportedly low toxicity and is routinely employed in ecotoxicology, very little is known about its effect on dynamic behavioral parameters. This study presents a comparative analysis of the lethal and behavioral effects of exposures to DMSO concentrations of 0.1–10% on several test species such as: neonates of the freshwater crustacean Daphnia magna, nauplii of the marine crustacean Artemia franciscana, the marine crustacean Allorchestes compressa, embryos and larvae of the freshwater fish Danio rerio. The results demonstrated that DMSO did not cause statistically significant mortality even at concentrations close to 1% but induced clear and significant behavioral abnormalities in response to sublethal concentrations on all test species. These included hypoactivity syndrome in A. franciscana, A. compressa, D. magna and zebrafish larvae while a slight time-dependent hyperactivity response was observed in zebrafish embryos. For the majority of test species, behavioral changes such as moving distance, acceleration and burst movement were often observed during the first hours of exposure. These results indicate that caution should be exercised when using DMSO as a carrier solvent in experiments assessing behavioral endpoints., This work was supported by the Australian Research Council (number DECRA DE13010104) and China Scholarship Council (number 201307000003).

Aquatic toxicity testing in environmental monitoring and chemical risk assessment is critical to assess water quality for human use as well as predict impact of pollutants on ecosystems. In recent years, studies have increasingly focused on the relevance of sub-lethal effects of environmental contaminants. Sub-lethal toxicity endpoints such as behavioural responses are highly integrative and have distinct benefits for assessing water quality because they occur rapidly and thus can be used to sense the presence of toxicants. Our work describes a Lab-on-a-Chip system for the automated analysis of freshwater cladoceran Daphnia magna locomotory responses to water-born toxicants. The design combines a Lab-on-a-Chip system for Daphnia sp. culture under perfusion with time-resolved videomicroscopy and software tracking locomotory activity of multiple specimens. The application of the system to analyse the swimming behaviour of water fleas exposed to different concentrations of water-born toxicants demonstrated that Lab-on-a-Chip devices can become important research tools for behavioural ecotoxicology and water quality biomonitoring., This study was funded by Australian Research Council DECRA DE130101046 (D.W.); Vice-Chancellor’s Senior Research Fellowship, RMIT University (D.W.); China Scholarship Council No.201307000003 (Y.H.).

The accurate tracking of zebrafish larvae movement is fundamental to research in many biomedical, pharmaceutical, and behavioral science applications. However, the locomotive characteristics of zebrafish larvae are significantly different from adult zebrafish, where existing adult zebrafish tracking systems cannot reliably track zebrafish larvae. Further, the far smaller size differentiation between larvae and the container render the detection of water impurities inevitable, which further affects the tracking of zebrafish larvae or require very strict video imaging conditions that typically result in unreliable tracking results for realistic experimental conditions. This paper investigates the adaptation of advanced computer vision segmentation techniques and multiple object tracking algorithms to develop an accurate, efficient and reliable multiple zebrafish larvae tracking system. The proposed system has been tested on a set of single and multiple adult and larvae zebrafish videos in a wide variety of (complex) video conditions, including shadowing, labels, water bubbles and background artifacts. Compared with existing state-of-the-art and commercial multiple organism tracking systems, the proposed system improves the tracking accuracy by up to 31.57% in unconstrained video imaging conditions. To facilitate the evaluation on zebrafish segmentation and tracking research, a dataset with annotated ground truth is also presented. The software is also publicly accessible.

Biotests performed on small vertebrate model organisms provide significant investigative advantages as compared with bioassays that employ cell lines, isolated primary cells, or tissue samples. The main advantage offered by whole-organism approaches is that the effects under study occur in the context of intact physiological milieu, with all its intercellular and multisystem interactions. The gap between the high-throughput cell-based in vitro assays and low-throughput, disproportionally expensive and ethically controversial mammal in vivo tests can be closed by small model organisms such as zebrafish or Xenopus. The optical transparency of their tissues, the ease of genetic manipulation and straightforward husbandry, explain the growing popularity of these model organisms. Nevertheless, despite the potential for miniaturization, automation and subsequent increase in throughput of experimental setups, the manipulation, dispensing and analysis of living fish and frog embryos remain labor-intensive. Recently, a new generation of miniaturized chip-based devices have been developed for zebrafish and Xenopus embryo on-chip culture and experimentation. In this work, we review the critical developments in the field of Lab-on-a-Chip devices designed to alleviate the limits of traditional platforms for studies on zebrafish and clawed frog embryo and larvae.

A new type of micro-nano hierarchical TiO 2 /SiO 2 composite film, which is formed by nanoparticles of TiO 2 deposited on microspheres of SiO 2 , has been prepared through a convenient and size-controllable method. A water-resistant agent (Aquapel PPG Co., USA) is grafted onto the composite films to achieve surface hydrophobicity. The morphologies, formations, and wettability of the novel films were investigated by field emission scanning electron microscopy (FE-SEM), X-ray photoelectron spectroscopy (XPS) and water contact angle (WCA), respectively. The results indicate that these composite films can achieve reversible wetting and are reproducible over several cycles of ultraviolet (UV) exposure and dark storage. The specific micro-nano structures enabled significant variation in wetting, due to the effect on both the hydrophilic and hydrophobic states of these tunable surfaces. Our study demonstrated that the wettability transition increased with decreased TiO 2 /SiO 2 size ratios, which resulted in a maximum wetting contrast in WCA of 103.8°, which is nearly twice the contrast of TiO 2 nano-structured film. A simple theoretical model was proposed to elucidate the correlation between size ratio and WCA, which indicated good agreement with the experimental data. These findings offer a new method for the design of intelligent surfaces with tailored and reversible wettability.

Microfluidic extraction based on a co-laminar flow of aqueous two-phase system is used to separate bovine serum albumin (BSA). Mass transfer between the continuous two-phase flows is demonstrated by the extraction of BSA in a microfluidic device. The protein concentrations of the BSA samples were determined using the Bradford method. Polyethylene glycol 4000 and ammonium sulfate ((NH4)2SO4) served as model aqueous two-phase solutions. The appropriate flow rates of the aqueous two phases were thus determined. We can flexibly control the mass transfer area and time by simply adjusting the flow rate. It takes only 3.6 s for three extraction cycles in a coaxial microfluidic device to achieve a BSA recovery yield of 71.1 %, which is superior to the traditional beaker aqueous two-phase extraction process. In this study, co-laminar flow-based continuous microextraction is demonstrated and its mass transfer is analyzed by solving the diffusion model, based on a large specific interfacial area and surface renewal.

Objective Uncontrolled hypertension (HTN) results in strokes, myocardial infarction (MI), and other complications, which are the leading cause of disability, death, and severe economic consequence. We conducted an economic evaluation to determine the costs and quality-adjusted life-years (QALYs) associated with amlodipine (Norvasc) and the angiotensin II receptor blockers (ARBs) in preventing stroke and MI among Chinese HTN patients. Methods A cost-utility analysis was conducted from the third-party payer perspective. A Markov model was constructed to estimate 5-year costs and health consequences of amlodipine and valsartan. Effectiveness data were based on a published meta-analysis. Utility data were retrieved from the published literature. Costs of MI were retrieved from China Health Statistics Yearbook. Costs of stroke were obtained from retrospective chart review and follow-up interviews in Chinese tertiary hospitals. Costs included costs of drugs, direct medical costs of HTN management, stroke/MI treatment, and follow-up management. Discounting rate used for costs and QALYs was 3%. Results Total direct medical and drug costs of amlodipine and valsartan (ARB) users were ¥111,731,716 and ¥132,058,611, respectively; total QALYs of amlodipine and valsartan users were 30,648.5 and 30,520.8, respectively. Amlodipine is dominant with lower costs and higher QALYs. This demonstrated that compared with valsartan, amlodipine is a cost-saving therapy with better QALY outcome. When irbesartan data were used in the comparison, the magnitude of cost saving changed but the overall conclusion remained the same. Conclusion Amlodipine is a cost-saving therapy compared with ARBs in preventing stroke and MI for Chinese HTN patients.

Biomonitoring studies apply biological responses of sensitive biomonitor organisms to rapidly detect adverse environmental changes such as presence of physic-chemical stressors and toxins. Behavioral responses such as changes in swimming patterns of small aquatic invertebrates are emerging as sensitive endpoints to monitor aquatic pollution. Although behavioral responses do not deliver information on an exact type or the intensity of toxicants present in water samples, they could provide orders of magnitude higher sensitivity than lethal endpoints such as mortality. Despite the advantages of behavioral biotests performed on sentinel organisms, their wider application in real-time and near realtime biomonitoring of water quality is limited by the lack of dedicated and automated video-microscopy systems. Current behavioral analysis systems rely mostly on static test conditions and manual procedures that are time-consuming and labor intensive. Tracking and precise quantification of locomotory activities of multiple small aquatic organisms requires high-resolution optical data recording. This is often problematic due to small size of fast moving animals and limitations of culture vessels that are not specially designed for video data recording. In this work, we capitalized on recent advances in miniaturized CMOS cameras, high resolution optics and biomicrofluidic technologies to develop near real-time water quality sensing using locomotory activities of small marine invertebrates. We present proof-of-concept integration of high-resolution time-resolved video recording system and high-throughput miniaturized perfusion biomicrofluidic platform for optical tracking of nauplii of marine crustacean Artemia franciscana.

An increased rigor in water quality monitoring is not only a legal requirement, but is also critical to ensure timely chemical hazard emergency responses and protection of human and animal health. Bioindication is a method that applies very sensitive living organisms to detect environmental changes using their natural responses. Although bioindicators do not deliver information on an exact type or intensity of toxicants present in water samples, they do provide an overall snapshot and early-warning information about presence of harmful and dangerous parameters. Despite the advantages of biotests performed on sentinel organisms, their wider application is limited by the nonexistence of high-throughput laboratory automation systems. As a result majority of biotests used in ecotoxicology require time-consuming and laborious manual procedures. In this work, we present development of a miniaturized Lab-on-a-Chip (LOC) platform for automation and enhancement of acute ecotoxicity test based on immobilization of a freshwater crustacean Daphnia magna (Daphtoxkit-FTM). Daphnids’ immobilization in response to sudden changes in environment parameters is fast, unambiguous, and easy to record optically. We also for the first time demonstrate that LOC system enables studies of sub-lethal ecotoxic effects using behavioral responses of Daphnia magna as sentinels of water pollution. The system working principle incorporated a high definition (HD) time-resolved video data analysis to dynamically assess impact of the reference toxicant on swimming behavior of D. magna. Our system design combined: (i) microfluidic device for caging of Daphnia sp.; (ii) mechatronic interface for fluidic actuation; (iii) video data acquisition; and (iv) algorithms for animal movement tracking and analysis.

Advances in microfabrication technologies and manufacturing over last decade, allowed for inexpensive prototyping of microfluidic chip-based devices for biomedical studies in biocompatible and optically transparent elastomeric polymers such as poly(dimethylsiloxane) (PDMS) and thermoplastics such as poly(methyl methacrylate) (PMMA). More resently, advanced additive manufacturing technologies such as stereolithography (SLA), capable of reproducing feature sizes less than 50 μm, pave a way towards a new generation of microfabrication techniques. The latter promise new methods to enable accelerated design, validation and optimisation of optical-grade biomicrofluidic Lab-on-a-Chip (LOC) devices. The main limitation, however, of virtually all polymers that are used to both manufacture LOC devices as well as to provide fluidic interconnects is their significant hydrophobicity. Conventionally the hydrophobic properties were postulated to impede wetting and priming of the polymeric chip-based devices and tubing interconnects. Such issues were often solved with plasma treatment or ethanol priming to help wet the polymeric substrata and also reduce the nucleation and persistence of air bubbles. In this work, we present evidence that use of certain hydrophobic polymers is a significant impediment in performing ecotoxicity tests of organic chemicals on biomicrofluidic devices. We report on electrostatic interaction between polymers and toxicants that lead to non-covalent adsorption and rapid depletion of chemicals from the tested media. This introduces a significant bioanalytical bias irrespectively of the fact that microfluidic tests are preformed under continuous perfusion.

Behavioral ecotoxicity tests are gaining an increasing recognition in environmental toxicology. Behavior of sensitive bioindicator species can change rapidly in response to an acute exposure to contaminants and thus has a much higher sensitivity as compared to conventional LC50 mortality tests. Furthermore, behavioral endpoints seems to be very good candidates to develop early-warning biomonitoring systems needed for rapid chemical risk assessment. Behavioral tests are non-invasive, fast, do not harm indicator organisms (behavioural changes are very rapid) and are thus fully compatible with 3R (Replacement – Reduction – Refinement) principle encouraging alternatives to conventional animal testing. These characteristics are essential when designing improved ecotoxicity tests for chemical risk assessment. In this work, we present a pilot development of miniaturized Lab-on-a-Chip (LOC) devices for studying toxin avoidance behaviors of small aquatic crustaceans. As an investigative tool, LOCs represent a new direction that may miniaturize and revolutionize behavioral ecotoxicology. Specifically our innovative microfluidic prototype: (i) enables convening “caging” of specimens for real-time videomicroscopy; (ii) eliminates the evaporative water loss thus providing an opportunity for long-term behavioral studies; (iii) exploits laminar fluid flow under low Reynolds numbers to generate discrete domains and gradients enabling for the first time toxin avoidance studies on small aquatic crustaceans; (iv) integrates off-the-chip mechatronic interfaces and video analysis algorithms for single animal movement analysis. We provide evidence that by merging innovative bioelectronic and biomicrofluidic technologies we can deploy inexpensive and reliable systems for culture, electronic tracking and complex computational analysis of behavior of bioindicator organisms.

Changes in behavioral traits exhibited by small aquatic invertebrates are increasingly postulated as ethically acceptable and more sensitive endpoints for detection of water-born ecotoxicity than conventional mortality assays. Despite importance of such behavioral biotests, their implementation is profoundly limited by the lack of appropriate biocompatible automation, integrated optoelectronic sensors, and the associated electronics and analysis algorithms. This work outlines development of a proof-of-concept miniaturized Lab-on-a-Chip (LOC) platform for rapid water toxicity tests based on changes in swimming patterns exhibited by Artemia franciscana (Artoxkit M™) nauplii. In contrast to conventionally performed end-point analysis based on counting numbers of dead/immobile specimens we performed a time-resolved video data analysis to dynamically assess impact of a reference toxicant on swimming pattern of A. franciscana . Our system design combined: (i) innovative microfluidic device keeping free swimming Artemia sp. nauplii under continuous microperfusion as a mean of toxin delivery; (ii) mechatronic interface for user-friendly fluidic actuation of the chip; and (iii) miniaturized video acquisition for movement analysis of test specimens. The system was capable of performing fully programmable time-lapse and video-microscopy of multiple samples for rapid ecotoxicity analysis. It enabled development of a user-friendly and inexpensive test protocol to dynamically detect sub-lethal behavioral end-points such as changes in speed of movement or distance traveled by each animal.

Requirement Engineering (RE) has become an attractive field in both industry and academic. Many RE approaches have been presented in the past years to support eliciting, modeling, analyzing and specifying requirements of system to be built. However, requirement characteristics of kinds of systems like large scale software intensive systems pose several issues to requirements analysis and therefore challenge the extant RE approaches. This paper investigates a number of important metaphors in RE and proposes a novel RE approach that adopts capability as requirement metaphor. We discuss the requirements challenges coming from the changes of system-to-be and argue the necessity to introduce new abstraction and technology into RE to deal with the problems. The notions of capability and the reason to adopt capability as requirement metaphor are analyzed. The meta-model and framework of capability-based requirement engineering is proposed. A case is also studied in order to illustrate our approach. Capability as new abstraction in RE provides a new way to represent, analyze and tradeoff requirements.

Aiming at the actual engineering problem of influence of foundation pit excavation on underground pipelines nearby, basing on elastic foundation beam theory, the calculation method based on field test ground settlement curve of calculating the influence of foundation pit excavation on underground pipeline nearby is proposed. This method makes up the shortage of supposing the ground settlement curve above underground pipeline to be parabola, which makes the calculation result more accurate. Finally, the solution process of this method is illustrated through an engineering example. The vertical displacement equation of underground pipeline is obtained, and its value solution is solved with Matlab software, which is in good agreement with that of field test.