694 research outputs found
Cytotoxicity Effects of Amoora rohituka and chittagonga on Breast and Pancreatic Cancer Cells
Chemotherapeutic agents for cancer are highly toxic to healthy tissues and hence alternative medicine avenues are widely researched. Majority of the recent studies on alternative medicine suggested that Amoora rohituka possesses considerable antitumor and antibacterial properties. In this work, rohituka and chittagonga, fractionated with petroleum ether, dichloromethane, and ethanol, were explored for their anticancer potential against two breast cancer (MCF-7 and HTB-126) and three pancreatic cancer (Panc-1, Mia-Paca2, and Capan1). The human foreskin fibroblast, Hs68, was also included. Cytotoxicity of each extract was analyzed using the MTT assay and label-free photonic crystal biosensor assay. A concentration series of each extract was performed on the six cell lines. For MCF-7 cancer cells, the chittagonga (Pet-Ether and CH2Cl2) and rohituka (Pet-Ether) extracts induced cytotoxicity; the chittagonga (EtoAC) and rohituka (MeOH) extracts did not induce cytotoxicity. For HTB126, Panc-1, Mia-Paca2, and Capan-1 cancer cells, only the chittagonga CH2Cl2 extract showed a significant cytotoxic effect. The extracts were not cytotoxic to normal fibroblast Hs68 cells, which may be correlated to the specificity of Amoora extracts in targeting cancerous cells. Based on these results, further examination of the potential anticancer properties Amoora species and the identification of the active ingredients of these extracts is warranted
Experimental techniques to assess coral physiology in situ under global and local stressors : current approaches and novel insights
This study was supported by the Hong Kong Branch of Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou; SMSEGL20SC02); the Collaborative Research Fund (C7013-19G) of the Hong Kong Research Grants Council; the National Natural Science Foundation of China (41641047); the Internal Research Project of State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, State Oceanic Administration (no. SOEDZZ1702); and the SKLMP Seed Collaborative Research Fund (SCRF/0027).Coral reefs are declining worldwide due to global changes in the marine environment. The increasing frequency of massive bleaching events in the tropics is highlighting the need to better understand the stages of coral physiological responses to extreme conditions. Moreover, like many other coastal regions, coral reef ecosystems are facing additional localized anthropogenic stressors such as nutrient loading, increased turbidity, and coastal development. Different strategies have been developed to measure the health status of a damaged reef, ranging from the resolution of individual polyps to the entire coral community, but techniques for measuring coral physiology in situ are not yet widely implemented. For instance, while there are many studies of the coral holobiont response in single or limited-number multiple stressor experiments, they provide only partial insights into metabolic performance under more complex and temporally and spatially variable natural conditions. Here, we discuss the current status of coral reefs and their global and local stressors in the context of experimental techniques that measure core processes in coral metabolism (respiration, photosynthesis, and biocalcification) in situ, and their role in indicating the health status of colonies and communities. We highlight the need to improve the capability of in situ studies in order to better understand the resilience and stress response of corals under multiple global and local scale stressors.Publisher PDFPeer reviewe
The Feasibility of Integrating the Noble Scallop Mimachlamys nobilis with Existing Fish Monoculture Farms in the South China Sea: A Bioeconomic Assessment from Hong Kong
The environmental implications of integrated multitrophic aquaculture have been well studied in China, but few investigations have empirically explored potential economic benefits. This study investigated the technical and economic feasibility of physically integrating the noble scallop Mimachlamys nobilis (Reeve, 1852) with existing fish monoculture farms in Hong Kong. Scallops were grown for 201 days from June to December in lantern nets hung directly from fish farm platforms at treatment depths of 1, 3.5, and 6 m. Only the 1-m treatment attained the target mean height-at-harvest of 80 mm. Fitted von Bertalanffy growth functions showed significant differences in growth performance between depths. The von Bertalanffy growth function projected that the 3.5- and 6-m treatments would require an additional 26 and 59 days of culture to reach 80 mm. Mortality was significantly lower at 1 m (53% ± 12.5%) compared with those at 3.5 m (70% ± 9.0%) and 6 m (83% ± 4.5%). The slower growth and higher mortality at 3.5 and 6mwere probably due to periodically low oxygen which dropped to 4.96, 3.08, and 1.73 mg L-1 at 1, 3.5, and 6 m, respectively, in midsummer. A bioeconomic assessments of two typical farm sizes was conducted; small (45 m2) and large (315 m2). The initial investment, discounted payback time, and 10-y net present value of the projects was US20,211.33, respectively, for the small farm and US227,406.49, respectively, for the large farm. Sensitivity analysis revealed that the profitability of operations was sensitive to changes in mortality and sales price. This study has confirmed that physically integrating M. nobilis at existing fish farms is technically and economically feasible
The impacts of suspended mariculture on coastal zones in China and the scope for Integrated Multi-Trophic Aquaculture
Introduction: China is responsible for more than 60\% of global aquaculture production. As the frontiers of food production have expanded, the cultivation of marine organisms in coastal zones and the open ocean has grown rapidly. The dominant mariculture industry in China is suspended mariculture, which uses net cages, ropes, or other structures suspended in the water column to cultivate aquatic organisms. This systematic, quantitative review provides a clear and comprehensive account of research that has investigated the adverse impacts of suspended mariculture in China and reviews research that has applied Integrated Multi-Trophic Aquaculture (IMTA) systems for mitigating impacts. This work builds on 218 peer reviewed papers that have been published in English-language journals. Outcomes: Eighteen impacts were identified, including chemical, ecological, physical, and socioeconomic impacts. Eighteen measures for improving suspended mariculture were recommended consisting of government department, farm management, and ecological engineering measures. IMTA was the most frequently recommended measure. The capabilities of IMTA for bioremediation and increased farm production were the most frequently studied advantages. Seven other benefits have been explored but remain understudied. The current challenges facing the expansion of commercial IMTA include limited use of new technology, limited skills development, decreasing production of low trophic-level species, biogeographic and temporal barriers, and negative system feedbacks. Conclusion: Despite challenges, implementing commercial IMTA is a promising measure for reducing the impacts of suspended mariculture because it presents a range of secondary benefits that can improve the overall sustainability of aquaculture in the coastal zone
Tropism of and Innate Immune Responses to the Novel Human Betacoronavirus Lineage C Virus in Human Ex Vivo Respiratory Organ Cultures
Since April 2012, there have been 17 laboratory-confirmed human cases of respiratory disease associated with newly recognized human betacoronavirus lineage C virus EMC (HCoV-EMC), and 7 of them were fatal. The transmissibility and pathogenesis of HCoV-EMC remain poorly understood, and elucidating its cellular tropism in human respiratory tissues will provide mechanistic insights into the key cellular targets for virus propagation and spread. We utilized ex vivo cultures of human bronchial and lung tissue specimens to investigate the tissue tropism and virus replication kinetics following experimental infection with HCoV-EMC compared with those following infection with human coronavirus 229E (HCoV-229E) and severe acute respiratory syndrome coronavirus (SARS-CoV). The innate immune responses elicited by HCoV-EMC were also investigated. HCoV-EMC productively replicated in human bronchial and lung ex vivo organ cultures. While SARS-CoV productively replicated in lung tissue, replication in human bronchial tissue was limited. Immunohistochemistry revealed that HCoV-EMC infected nonciliated bronchial epithelium, bronchiolar epithelial cells, alveolar epithelial cells, and endothelial cells. Transmission electron microscopy showed virions within the cytoplasm of bronchial epithelial cells and budding virions from alveolar epithelial cells (type II). In contrast, there was minimal HCoV-229E infection in these tissues. HCoV-EMC failed to elicit strong type I or III interferon (IFN) or proinflammatory innate immune responses in ex vivo respiratory tissue cultures. Treatment of human lung tissue ex vivo organ cultures with type I IFNs (alpha and beta IFNs) at 1 h postinfection reduced the replication of HCoV-EMC, suggesting a potential therapeutic use of IFNs for treatment of human infection
Time Course and Cellular Localization of SARS-CoV Nucleoprotein and RNA in Lungs from Fatal Cases of SARS
BACKGROUND: Cellular localization of severe acute respiratory syndrome coronavirus (SARS-CoV) in the lungs of patients with SARS is important in confirming the etiological association of the virus with disease as well as in understanding the pathogenesis of the disease. To our knowledge, there have been no comprehensive studies investigating viral infection at the cellular level in humans. METHODS AND FINDINGS: We collected the largest series of fatal cases of SARS with autopsy material to date by merging the pathological material from two regions involved in the 2003 worldwide SARS outbreak in Hong Kong, China, and Toronto, Canada. We developed a monoclonal antibody against the SARS-CoV nucleoprotein and used it together with in situ hybridization (ISH) to analyze the autopsy lung tissues of 32 patients with SARS from Hong Kong and Toronto. We compared the results of these assays with the pulmonary pathologies and the clinical course of illness for each patient. SARS-CoV nucleoprotein and RNA were detected by immunohistochemistry and ISH, respectively, primarily in alveolar pneumocytes and, less frequently, in macrophages. Such localization was detected in four of the seven patients who died within two weeks of illness onset, and in none of the 25 patients who died later than two weeks after symptom onset. CONCLUSIONS: The pulmonary alveolar epithelium is the chief target of SARS-CoV, with macrophages infected subsequently. Viral replication appears to be limited to the first two weeks after symptom onset, with little evidence of continued widespread replication after this period. If antiviral therapy is considered for future treatment, it should be focused on this two-week period of acute clinical disease
Preparation of an ion with the highest calculated proton affinity: ortho-diethynylbenzene dianion
Owing to the increased proton affinity that results from additional negative charges, multiply-charged anions have been proposed as one route to prepare and access a range of new and powerful superbases . Paradoxically, while the additional electrons in polyanions increase basicity they serve to diminish the electron binding energy and thus, it had been thought, hinder experimental synthesis. We report the synthesis and isolation of the ortho-diethynylbenzene dianion (ortho-DEB2−) and present observations of this novel species undergoing gas-phase proton-abstraction reactions. Using a theoretical model based on Marcus-Hush theory, we attribute the stability of ortho-DEB2− to the presence of a barrier that prevents spontaneous electron detachment. The proton affinity of 1843 kJ mol−1 calculated for this dianion superbase using high-level quantum chemistry calculations significantly exceeds that of the lithium monoxide anion, the most basic system previously prepared. The ortho-diethynylbenzene dianion is therefore the strongest base that has been experimentally observed to date
Distribution, abundance and diversity of Gambierdiscus spp. from a ciguatera endemic area in Marakei, Republic of Kiribati
Author Posting. © The Author(s), 2014. This is the author's version of the work. It is posted here by permission of Elsevier for personal use, not for redistribution. The definitive version was published in Harmful Algae 34 (2014): 56–68, doi:10.1016/j.hal.2014.02.007.Ciguatera is a serious seafood poisoning syndrome caused by the consumption of
ciguatoxin-contaminated finfish from tropical and subtropical regions. This study
examined the community structure of ciguatera-associated dinoflagellates and the
distribution pattern, taxonomy and toxicity of Gambierdiscus spp. from a high-risk area
of Marakei, Republic of Kiribati. The genera Gambierdiscus, Prorocentrum, Ostreopsis,
Amphidinium and Coolia were present, and generally the former three dominated the
dinoflagellate assemblage. Among these three, Gambierdiscus was the most abundant
dinoflagellate genus observed at three of the four sites sampled, two of which (Sites 1 and
2) were on the northern half of the island and two (Sites 3 and 4) on the southern half.
The following patterns of abundance were observed among sites: (1) Average
Gambierdiscus spp. abundance at the northern sites exceeded the southern sites by a
factor of 19-54; and (2) Gambierdiscus spp. abundance at shallow sites (2-3 m) exceeded
deeper sites (10-15 m). The distribution of Gambierdiscus spp. at Marakei corresponded
with previously observed patterns of fish toxicity, with fish from southern locations being
much less toxic than fish sampled north of the central channel. DNA sequencing
identified three Gambierdiscus species (G. carpenteri, G. belizeanus, G. pacificus) and
three previously unreported ribotypes (Gambierdiscus sp. type 4, Gambierdiscus sp. type
5, Gambierdiscus sp. type 6) in the samples; Gambierdiscus sp. type 4 may represent a
Pacific clade of Gambierdiscus sp. ribotype 1. Toxicity analyses determined that
Gambierdiscus sp. type 4 isolates were more toxic than the Gambierdiscus sp. type 5 and
G. pacificus isolates, with toxin contents of 2.6-6.0 (mean: 4.3± 1.4), 0.010 and 0.011 fg
P-CTX-1 eq cell-1, respectively. Despite low densities of
Gambierdiscus spp. observed at
Marakei relative to other studies in other parts of the world, the presence of low and
moderately toxic populations may be sufficient to render the western coast of Marakei a
high-risk area for ciguatera. The long history of toxicity along the western side of
Marakei suggests that large-scale oceanographic forcings that regulate the distribution of
Gambierdiscus spp. along the western side of Marakei may have remained relatively
stable over that time. Chronic as well as acute exposure to ciguatoxins may therefore
pose an important human health impact to the residents of Marakei.Funding for this work was provided by the
Centers for Disease Control and Prevention (U01 EH000421), USFDA
(F223201000060C), NOAA NOS (Cooperative Agreement NA11NOS4780060,
NA11NOS4780028), National Program on Key Basic Research Project of China (973
Program, 2013CB956503), the Nonprofit Research Project for the State Oceanic
Administration (China, 201005006-01), and the National Natural Science Foundation of
China (41276110)
Numerical Investigation of the Performance of Three Hinge Designs of Bileaflet Mechanical Heart Valves
Thromboembolic complications (TECs) of bileaflet mechanical heart valves (BMHVs) are believed to be due to the nonphysiologic mechanical stresses imposed on blood elements by the hinge flows. Relating hinge flow features to design features is, therefore, essential to ultimately design BMHVs with lower TEC rates. This study aims at simulating the pulsatile three-dimensional hinge flows of three BMHVs and estimating the TEC potential associated with each hinge design. Hinge geometries are constructed from micro-computed tomography scans of BMHVs. Simulations are conducted using a Cartesian sharp-interface immersed-boundary methodology combined with a second-order accurate fractional-step method. Leaflet motion and flow boundary conditions are extracted from fluid–structure-interaction simulations of BMHV bulk flow. The numerical results are analyzed using a particle-tracking approach coupled with existing blood damage models. The gap width and, more importantly, the shape of the recess and leaflet are found to impact the flow distribution and TEC potential. Smooth, streamlined surfaces appear to be more favorable than sharp corners or sudden shape transitions. The developed framework will enable pragmatic and cost-efficient preclinical evaluation of BMHV prototypes prior to valve manufacturing. Application to a wide range of hinges with varying design parameters will eventually help in determining the optimal hinge design
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