1,066 research outputs found

    Knockdown of Dinoflagellate Cellulose Synthase CesA1 Resulted in Malformed Intracellular Cellulosic Thecal Plates and Severely Impeded Cyst-to-Swarmer Transition

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    Cellulose synthesis (CS) is conducted by membrane-bound cellulose synthase complexes (CSCs), containing cellulose synthases (CesA), that are either arranged in hexagonal structures in higher plants or in linear arrays in most microbial organisms, including dinoflagellates. Dinoflagellates are a major phytoplankton group having linear-type CSCs and internal cellulosic thecal plates (CTPs) in large cortical vesicles. Immunological study suggested CesA1p were cortically localized to the periphery of CTPs. During cyst-to-swarmer transition (TC–S), synchronized peaks of CesA1 transcription, CesA1p expression, CS and CTP formation occurred in respective order, over 12–16 h, strategically allowing the study of CS regulation and CTP biogenesis. CesA1-knockdown resulted in 40% reduction in CesA1p level and time required for swarmer cells reappearance. CTPs were severely malformed with reduced cellulose content. As CTPs are deposited in internal organelle, the present study demonstrated dinoflagellate CesA1 ortholog was adapted for non-surface deposition; this is different to paradigm of other CesAps which require plasmamembrane for cellulose fiber deposition. This pioneer gene-knockdown study demonstrated the requirement of a gene for dinoflagellate cell wall remodeling and proper TC–S, which are prominent in dinoflagellate life-cycles

    Fictional Worlds, Real Connections: Developing Community Storytelling Social Chatbots through LLMs

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    We address the integration of storytelling and Large Language Models (LLMs) to develop engaging and believable Social Chatbots (SCs) in community settings. Motivated by the potential of fictional characters to enhance social interactions, we introduce Storytelling Social Chatbots (SSCs) and the concept of story engineering to transform fictional game characters into "live" social entities within player communities. Our story engineering process includes three steps: (1) Character and story creation, defining the SC's personality and worldview, (2) Presenting Live Stories to the Community, allowing the SC to recount challenges and seek suggestions, and (3) Communication with community members, enabling interaction between the SC and users. We employed the LLM GPT-3 to drive our SSC prototypes, "David" and "Catherine," and evaluated their performance in an online gaming community, "DE (Alias)," on Discord. Our mixed-method analysis, based on questionnaires (N=15) and interviews (N=8) with community members, reveals that storytelling significantly enhances the engagement and believability of SCs in community settings

    Moderate Alcohol Use and Mortality from Ischaemic Heart Disease: A Prospective Study in Older Chinese People

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    Abstract Background: Moderate alcohol use is generally associated with lower ischaemic heart disease (IHD) mortality but it is difficult to ascertain whether this is due to attributes of moderate alcohol users or the properties of alcohol itself. Evidence from populations with different patterns of alcohol use and IHD can provide crucial evidence. We assessed the association of moderate alcohol use with IHD mortality in older Chinese people from Hong Kong. Methodology We used Cox regression to determine whether moderate alcohol use was associated with IHD mortality in a prospective, population-based cohort study of all 56167 attendees, aged 65 years or over, from July 1998 to December 2000 at all 18 Elderly Health Centers operated by the Department of Health in Hong Kong. Principal Findings After a median follow-up of 4.2 years, there were 406 (188 in men, 218 in women) deaths from IHD in 54,090 subjects (96.3% successful follow-up). Moderate alcohol use in men was not associated with IHD mortality adjusted only for age [Hazard Ratio, HR 1.01 (95% CI 0.55 to 1.84) compared with never drinkers] or additionally adjusted for socioeconomic status and lifestyle. Almost all women were occasional drinkers and their current alcohol use was not significantly associated with IHD mortality [HR 0.88, (95% CI 0.51 to 1.53)]. Conclusions Moderate alcohol use had no effect on IHD mortality in older Chinese men. Lack of replication of the usual protective effect of moderate alcohol use in a setting with a different pattern of alcohol use and IHD could be due to chance or could suggest that the protective effect of alcohol on IHD does not extend to all populations

    Effect of laser treatment on the attachment and viability of mesenchymal stem cell responses on shape memory NiTi alloy

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    The objectives of this study were to investigate the effect of laser-induced surface features on the morphology, attachment and viability of mesenchymal stem cells (MSCs) at different periods of time, and to evaluate the biocompatibility of different zones: laser-melted zone (MZ), heat-affected zone (HAZ) and base metal (BM) in laser-treated NiTi alloy. The surface morphology and composition were studied by scanning electron microscope (SEM) and X-ray photoemission spectroscopy (XPS), respectively. The cell morphology was examined by SEM while the cell counting and viability measurements were done by hemocytometer and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric assay. The results indicated that the laser-induced surface features, such as surface roughening, presence of anisotropic dendritic pattern and complete surface Ni oxidation were beneficial to improve the biocompatibility of NiTi as evidenced by the highest cell attachment (4 days of culture) and viability (7 days of culture) found in the MZ. The biocompatibility of the MZ was the best, followed by the BM with the HAZ being the worst. The defective and porous oxide layer as well as the coarse grained structure might attribute to the inferior cell attachment (4 days of culture) and viability (7 days of culture) on the HAZ compared with the BM which has similar surface morphology. © 2014 Elsevier B.V

    Symptomatic epidural gas cyst treated with epidural block and percutaneous needle aspiration -A case report-

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    A 68-year-old woman suffered from lower back and radiating pain on her right buttock and posterior calf. Axial magnetic resonance imaging showed a 7 × 7 mm nodular lesion (T1 and, T2 low signal intensity) at the epidural space between the L5-S1 level and computed tomography revealed it was an epidural gas cyst. The authors performed an epidural block and percutaneous needle aspiration of the epidural gas cyst. The patient showed almost complete resolution of symptoms one year later. The authors suggest that an epidural nerve block with needle aspiration of a gas cyst could be an alternative treatment option for patients with a symptomatic epidural gas cyst before surgery

    Coronary-artery Calcium Scores Using Electron Beam CT in Patients with Chronic Renal Failure

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    We evaluated the risk of coronary-artery disease in patients with chronic renal failure (CRF) by measuring the coronary-artery calcium scores with electron beam CT (EBCT). A total of 81 CRF patients were divided into three groups; pre-dialysis (group I, n=35), hemodialysis (group II, n=31) and peritoneal dialysis (group III, n=15). The several serum biochemical markers and calcium score levels by EBCT were determined. The Ca×P products were significantly higher in groups II (p<0.05) and III (p<0.01) than in group I. The serum calcium levels were significantly higher in group III than in both group I (p<0.01) and II (p<0.05). The serum calcium level in 15 patients with a calcium score > 400 was significantly higher than the 66 patients with a score ≤400 (p<0.01). The calcium score was significantly higher in the 15 patients with cardiovascular complications than in the 66 patients without cardiovascular complications (628.9±904.8 vs. 150.4±350.9, p<0.01). EBCT seemed to be a good diagnostic tool for evaluating the risk of coronary-artery disease "non-invasively" in CRF patients who are at increased risk of cardiovascular morbidity and mortality
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