Continued nucleic acid tests for SARS-CoV-2 following discharge of patients with COVID-19 in Lu’an, China

Background Studies have shown that discharged Coronavirus disease 2019 (COVID-19) patients have retested positive for SARS-CoV-2 during a follow-up RT-PCR test. We sought to assess the results of continued nucleic acid testing for SARS-CoV-2 patients in COVID-19 patients after they were discharged in Lu’an, China. Methods We conducted RT-PCR tests on sputum, throat swabs, fecal or anal swabs, and urine samples collected from 67 COVID-19 patients following discharge. Samples were collected on the 7th and 14th days following discharge. Patients testing positive on the 7th or 14th day were retested after 24 hours until they tested negative twice. Results Seventeen (17/67, 25.4%) discharged COVID-19 patients had a positive RT-PCR retest for SARS-CoV-2. Among them, 14 (82.4%) were sputum positive, five (29.4%) were throat swab positive, seven (41.2%) were fecal or anal swab positive, one (5.9%) was urine sample positive, five (29.4%) were both sputum and throat swab positive, four (23.5%) were both sputum and fecal test positive, and one (5.9%) was positive of all four specimens. The shortest period of time between discharge and the last positive test was 7 days, the longest was 48 days, and the median was 16 days. The proportion of positive fecal or anal swab tests increased from the third week. The median Cq cut-off values after onset were 26.7 after the first week, 37.7 the second to sixth week, and 40 after the sixth week. There were no significant differences between the RT-PCR retest positive group and the unrecovered positive group. Conclusions There was a high proportion of patients who retested positive for COVID-19. Discharge criteria have remained fairly consistent so we encourage regions affected by COVID-19 to appropriately amend their current criteria

Maintaining the order: How social crowding promotes minimalistic consumption practice

Although minimalism has come to the forefront of contemporary consumer culture, neither its antecedents nor the psychological process that drives minimalistic consumption have been systematically established in the literature. This study documents a novel effect of social crowding, one common environmental cue, on minimalistic consumption practice. Across five experimental studies, we explore how exposure to social crowding motivates consumers to engage in minimalistic consumption as a means of coping with their experience of chaos and maintaining their psychological need for order. Furthermore, we demonstrate that the uncovered effects do not occur when a crowded environment is composed of familiar in-group members or when consumers have an interdependent self-construal. The findings therefore not only provide novel insights that extend the literature but also have certain implications for corporations seeking to promote minimalistic consumption practice

When is sustainability an asset? The interaction effects between the green attributes and product category

Purpose Products that espouse environmental ethical principles have received increasing attention in recent years. However, one key barrier against sustainable consumption is that green attributes could result in consumer’s expectation of decreased product physical performance. This study aims to investigate how green attributes existing in different product categories affect consumer purchase intention. Design/methodology/approach Two experimental studies were conducted to test the hypotheses. Study 1 provides initial evidence of the interaction effects between green attributes and product category on consumer purchase intention. Study 2 replicates the findings of Study 1 and further tests a benefits-based mechanism in the relationship between green attributes and consumer purchase intention. Findings The findings show that in the utilitarian product category, products with green peripheral attributes result in a higher purchase intention than those with green core attributes, whereas, in the hedonic product category, products with green core attributes result in a higher purchase intention than those with green peripheral attributes. Furthermore, the authors demonstrate that green attributes, as universal sustainability cues predominantly affect consumers’ perceptions of utilitarian environmental benefits and self-expression benefits, which further enhance their purchase intention towards utilitarian products and hedonic products, respectively. Originality/value This study responds to the calls for more empirical studies into discussing the role of green attributes in consumer purchase intention. Furthermore, it uncovers a benefits-based mechanism that explains how green attributes existing in utilitarian product categories and hedonic product categories trigger consumers’ analysis of benefits, leading to positive consumer purchase intention

Effective control of Poterioochromonas malhamensis in pilot-scale culture of Chlorella sorokiniana GT-1 by maintaining CO2-mediated low culture pH

Although predators in microalgal culture can often be protozoa reducing biomass productivity and culture stability, there are few effective approaches to control them. This study investigated the effect of culture pH (i.e., 6.0, 6.5, 7.0 and 7.5) maintained by supply of compressed air bubbles containing various concentrations of CO2 on death of the flagellate Poterioochromonas malhamensis and several other protozoa in the culture of the green microalgae Chlorella sorokiniana GT-1. C. sorokiniana GT-1 grew well at pH 6.0 and 6.5 and a sustainable biomass concentration of 1.61 g L-1 was obtained from the cultures maintained at pH 6.5. The cultures maintained at pH 7.0 and 7.5 collapsed on days 7 and 4 of culture, respectively, as a result of contamination by P. malhamensis and to less extent by other protozoa (e.g., ciliates and amoebae). Further experiments revealed that it was the actual dissolved CO2, not the low pH itself, or reduced dissolved oxygen in the culture medium that prevented the occurrence of P. malhamensis. It is speculated that increased CO2 partial pressure in the culture media may enhance diffusion of CO2 into the cytoplasm of P. malhamensis that lowers the intercellular pH, and thus results in cell death. The method developed in this study can be effective in protozoan control in pilot-scale Chlorella culture in an open raceway pond. It is suggested that a low pH maintained temporarily or constantly by supply of CO2 may be a promising approach to control P. malhamensis and alike in microalgal culture.</p

From Start to Finish: Latency Reduction Strategies for Incremental Speech Synthesis in Simultaneous Speech-to-Speech Translation

Speech-to-speech translation (S2ST) converts input speech to speech in another language. A challenge of delivering S2ST in real time is the accumulated delay between the translation and speech synthesis modules. While recently incremental text-to-speech (iTTS) models have shown large quality improvements, they typically require additional future text inputs to reach optimal performance. In this work, we minimize the initial waiting time of iTTS by adapting the upstream speech translator to generate high-quality pseudo lookahead for the speech synthesizer. After mitigating the initial delay, we demonstrate that the duration of synthesized speech also plays a crucial role on latency. We formalize this as a latency metric and then present a simple yet effective duration-scaling approach for latency reduction. Our approaches consistently reduce latency by 0.2-0.5 second without sacrificing speech translation quality.Comment: Accepted by Interspeech 202

Effect of recycling the culture medium on biodiversity and population dynamics of bio-contaminants in Spirulina platensis mass culture systems

Spirulina (Arthrospira) is an important microalga that can generate a variety of commercial products. A semi-continuous mode of cultivation is often employed in microalgal cultivation. The traditional view, however, has been that cultures with recycled medium are more likely to be contaminated by microzooplankton, which is regarded as one of the critical problems in mass algal cultivation. In this study, the relationship between the population dynamics of contaminants and the medium conditions was investigated in Spirulina cultures. Spirulina platensis was cultivated in three groups of raceway ponds: one with fresh culture medium, one with medium that had been recycled for a month, and the third with medium recycled for six months. The results showed that totally 13 species of microzooplankton were observed by light microscopy, and 42 operational taxonomic units (OTUs) of prokaryotic contaminants were detected using amplicon sequencing. Out of all the contaminants, Brachionus plicatilis and Euplaesiobystra hypersalinica were observed to be the most harmful species in Spirulina cultures, while Proteobacteria were the most commonly found non-Cyanobacteria OTUs. On the initial day, more species of microzooplankton were introduced to the cultures that had recycled medium (9 species) than to those that had fresh medium (5 species). By the end of the cultivation, the algal biomass in the fresh medium group was the highest (2.8 g L-1), being almost 5 times higher than in the other two groups (around 0.50 g L-1). Our results proved that Spirulina can grow the best with fresh medium and that the more the culture medium is recycled, the stronger the inhibition on the growth of microalgae and microzooplankton. In order to improve large-scale Spirulina production, it is necessary to both subject the recycled medium to appropriate treatment to reduce the presence of harmful predators and to find effective ways to control contaminants

From Start to Finish: Latency Reduction Strategies for Incremental Speech Synthesis in Simultaneous Speech-to-Speech Translation

Speech-to-speech translation (S2ST) converts input speech to speech in another language. A challenge of delivering S2ST in real time is the accumulated delay between the translation and speech synthesis modules. While recently incremental text-to-speech (iTTS) models have shown large quality improvements, they typically require additional future text inputs to reach optimal performance. In this work, we minimize the initial waiting time of iTTS by adapting the upstream speech translator to generate high-quality pseudo lookahead for the speech synthesizer. After mitigating the initial delay, we demonstrate that the duration of synthesized speech also plays a crucial role on latency. We formalize this as a latency metric and the present a simple yet effective duration-scaling approach for latency reduction. Our approaches consistently reduce latency by 0.2-0.5 second without sacrificing speech translation quality

Contaminating microzooplankton in outdoor microalgal mass culture systems: An ecological viewpoint

Ecological studies of contaminating microzooplankton in microalgal mass culture are important for large-scale cultivation risk management and remediation strategies, with the ultimate goal to ensure the sustainable high-yield production of microalgal biomass. Using multivariate statistical techniques, the characteristics and relationships with environmental variables of contaminating microzooplankton species were studied in commercial production of Spirulina platensis in outdoor raceway ponds in East and North China. A total of 16 microzooplankton species were identified from 64 large-scale raceway ponds, including three rotifers, two amoebae, and eleven ciliates. The relative abundance of individual microzooplankton species was in an order, from high to low, of ciliates > rotifers > amoebae. The ciliate Cyclidium marinum was the most frequently occurring species, mainly due to its wide tolerance of environmental conditions; and the rotifer Brachionus plicatilis was the key contaminating species, responsible for major loss of biomass productivity owing to its high level of occurrence and feed characteristics as an algivore. The high salinity habitats of the culture systems in North China featured the ciliate Frontonia didieri as an algophagous indicator species, while in East China the amoebae Nuclearia simplex and Euplaesiobystra hypersalinica were indicators for seed ponds and production ponds, respectively, attributed to the specific physicochemical conditions of the local environments. Fine tuning of salinity and pH away even temporarily from the optima of these contaminating microzooplankton species may be an easy and effective protocol for contamination control. Our investigation indicates the importance of comprehensively considering the environmental optima, tolerances and feed characteristics of contaminating species, together with continuous monitoring and ecological data analysis, for efficient management strategies geared towards the mitigation of biological contamination in microalgal mass culture. (C) 2016 Elsevier B.V. All rights reserved

Design of functional decellularized matrix for conjunctival epithelial stem cell maintenance and ocular surface reconstruction

Conjunctival defects severely impair ocular surface homeostasis and vision. However, the existing conjunctival reconstruction methods are still unable to achieve satisfactory functional replacement of conjunctiva. Scaffold materials that provide a more stem-cell-friendly microenvironment are in urgent need of improvement. Herein we reported a functional conjunctival reconstruction scaffold constructed from decellularized matrix derived from rabbit subconjunctival fibroblasts (DM-SCF) loaded with conjunctival epithelial stem cells (CjESCs) for ocular surface repair. The DM-SCF had a thickness and mechanical strength close to that of normal conjunctiva and showed excellent biocompatibility. CjESCs inoculated on DM-SCF maintained good stem cell properties, which showed long-term maintenance of low differentiation and good proliferation activity. DM-SCF transplantation with CjESCs showed satisfactory results in rabbit models of a large conjunctival defect. The conjunctiva was reconstructed with abundant goblet cell expression and regular fiber arrangement. Protein mass spectrometry revealed the active extracellular matrix components of DM-SCF, regulating the activation of Wnt/β-catenin and Notch pathways for stem cell maintenance. Overall, our study developed a promising new strategy for ocular surface reconstruction by optimizing bioactive scaffold and providing functional stem cell niche, so as to achieve long-standing and superior functional repair

Biodiversity and distribution of microzooplankton in Spirulina (Arthrospira) platensis mass cultures throughout China

Spirulina (Arthrospira) platensis is the most commonly produced microalgae for commercial applications, such as nutraceuticals and feed. While crop productivity of commercial Spirulina farms is often compromised by grazers and contaminating microzooplanktons, the biodiversity and identity of the most harmful microzooplanktons in Spirulina farms have not been extensively studied. As China is the number one producer of Spirulina in the world, comprehensive information on the biodiversity and identity of microzooplanktons in Spirulina farms is essential for the long-term commercial viability of these farms. Therefore, we determined the biodiversity and identity of the major microzooplanktons that are present in eight commercial Spirulina cultivation sites throughout China. Furthermore, we identified the major grazers that appear to directly affect the productivity of Spirulina cultures. Among twenty-three species that include 2 flagellates, 2 amoebae, 15 ciliates, and 4 rotifers, Brachionus plicatilis, Frontonia sp. and one unknown Heterolobosean amoeba appeared to be the most harmful to Spirulina due to their high density and ability to graze Spirulina. The similarity of the biodiversity and abundance of the microzooplankton was &gt; 80% among two out of eight mass cultivation sites (C and D), while the remaining cultivation sites exhibited their own unique microzooplankton biodiversity characteristics. Redundancy analysis (RDA) showed that there was a positive relationship between harmful species of Brachionus plicatilis and salinity, while the other two harmful species of Heterolobosean amoeba and Frontonia sp. had a positive relationship with oxidation-reduction potential (ORP). As this is the first report to identify the major harmful microzooplankton species in commercial Spirulina farms, our study not only provides a theoretical basis for the relationship between environmental factors and biodiversity of harmful grazers but also lays a scientific foundation for developing effective monitoring and management strategies for commercial Spirulina farms.</p