1,603 research outputs found

    Enteral intake of Aluminum Sulphate in acidic medium enhances absorption and alters tissue content of other trace elements in male albino rats

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    Background: Aluminium (Al) intoxication was recognised as a causal agent in p a t i ent s undergoing haemodialysis and then was linked to Alzheimer's disease. Nevertheless, environmental pollution with Al is mainly v i a drinking water, particularly when acidic rain falls on Al containing soil and bedrock. In addition, aluminium utens i l s are widely used for cooking. Therefore, an increasing concern is emerging for the role of pH in the absorption of aluminium from ingested food. Materials and methods: The objective of this study was to establish the effect of acidification with1 ml/dL of concentrated acetic acid on the absorption of aluminium from a 5 mM a l u mi n i u m sulphate\ solution taken orally in albino rats. Levels of Al, Ca, Cu, and Fe in plasma. brain, kidney, and liver were measured by atomic absorption. Results: The results indicate that acidification of Al salt solut ion wi t h acetic acid enhances its absorption. Increased plasma Al level (p<0.05) was associated with increased deposition in all tissues and a reduced overall body mass (p<0.05) and mass of cerebral hemispheres (p<0.01) re la t ive to the controls. The increased plasma levels of Al correlated positively with increased Al deposited in the kidney (r =0.790) l ive r (r = 0.967), and b r a i n (r=0.955) despite the blood brain barrier. Increased Al also correlated negatively with levels of Ca, Cu, and Fe in all tissues except in brain in which there was a positive correlation with Ca deposition. Conclusion: The study shows an increased absorption and deposition of Al in the tissues from rats ingesting acidified Al solution with acetic acid

    Influence of Nanoceramic-Plated Waste Carbon Fibers on Alkali-Activated Mortar Performance

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    Waste carbon fibers as reinforcing elements in construction materials have recently gained increasing interest from researchers, providing outstanding strength performance and a lower environmental footprint compared to virgin fibers. Combination with cement-free binders, namely alkali-activated materials, is becoming increasingly important for sustainable development in the construction industry. This paper presents results relating to the potential use of waste carbon fibers in alkali-activated mortars. The waste carbon fiber fraction utilized in this research is difficult to integrate as reinforcement in ceramic–cementitious matrices due to its agglomerated form and chemical inertness. For this reason, a nanoceramic coating pretreatment based on nanoclay has been implemented to attempt improvements in terms of deagglomeration, dispersibility, and compatibility with alkali-activated materials. After chemical–physical and microstructural analysis on the nanoclay-plated fibers (including X-ray diffraction, IR spectroscopy, contact angle measurements, and electron microscopy) mortars were produced with four different dosages of treated and untreated waste fibers (0.25 wt.%, 0.5 wt.%, 0.75 wt.%, and 1 wt.%). Mechanical tests and fractographic investigations were then performed. The nanoclay coating interacts compatibly with the waste carbon fibers and increases their degree of hydrophilicity to improve their deagglomeration and dispersion. Compared to the samples incorporating as-received fillers, the addition of nanoclay-coated fibers improved the strength behavior of the mortars, recording a maximum increase in flexural strength of 19% for a fiber content of 0.25 wt.%. This formulation is the only one providing an improvement in mechanical behavior compared to unreinforced mortar. Indeed, as the fibrous reinforcement content increases, the effect of the nanoclay is attenuated by mitigating the improvement in mechanical performance

    Influence of Nanoceramic-Plated Waste Carbon Fibers on Alkali-Activated Mortar Performance

    Get PDF
    Waste carbon fibers as reinforcing elements in construction materials have recently gained increasing interest from researchers, providing outstanding strength performance and a lower environmental footprint compared to virgin fibers. Combination with cement-free binders, namely alkali-activated materials, is becoming increasingly important for sustainable development in the construction industry. This paper presents results relating to the potential use of waste carbon fibers in alkali-activated mortars. The waste carbon fiber fraction utilized in this research is difficult to integrate as reinforcement in ceramic–cementitious matrices due to its agglomerated form and chemical inertness. For this reason, a nanoceramic coating pretreatment based on nanoclay has been implemented to attempt improvements in terms of deagglomeration, dispersibility, and compatibility with alkali-activated materials. After chemical–physical and microstructural analysis on the nanoclay-plated fibers (including X-ray diffraction, IR spectroscopy, contact angle measurements, and electron microscopy) mortars were produced with four different dosages of treated and untreated waste fibers (0.25 wt.%, 0.5 wt.%, 0.75 wt.%, and 1 wt.%). Mechanical tests and fractographic investigations were then performed. The nanoclay coating interacts compatibly with the waste carbon fibers and increases their degree of hydrophilicity to improve their deagglomeration and dispersion. Compared to the samples incorporating as-received fillers, the addition of nanoclay-coated fibers improved the strength behavior of the mortars, recording a maximum increase in flexural strength of 19% for a fiber content of 0.25 wt.%. This formulation is the only one providing an improvement in mechanical behavior compared to unreinforced mortar. Indeed, as the fibrous reinforcement content increases, the effect of the nanoclay is attenuated by mitigating the improvement in mechanical performance

    Social Alignment Contagion in Online Social Networks

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    Researchers have already observed social contagion effects in both in-person and online interactions. However, such studies have primarily focused on users’ beliefs, mental states, and interests. In this article, we expand the state of the art by exploring the impact of social contagion on social alignment, i.e., whether the decision to socially align oneself with the general opinion of the users on the social network is contagious to one’s connections on the network or not. The novelty of our work in this article includes: 1) unlike earlier work, this article is among the first to explore the contagiousness of the concept of social alignment on social networks; 2) our work adopts an instrumental variable approach to determine reliable causal relations between observed social contagion effects on the social network; and 3) our work expands beyond the mere presence of contagion in social alignment and also explores the role of population heterogeneity on social alignment contagion. Based on the systematic collection and analysis of data from two large social network platforms, namely, Twitter and Foursquare, we find that a user’s decision to socially align or distance from social topics and sentiments influences the social alignment decisions of their connections on the social network. We further find that such social alignment decisions are significantly impacted by population heterogeneity

    Bedside Endoscopic Ultrasound in Critically Ill patients

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    Background. The aim of this study was to evaluate the role and impact of EUS in the management of critically ill patients. Methods. We retrospectively identified all patients at our institution over a 68-month period in whom bedside inpatient EUS was performed. EUS was considered to have a significant impact if a new diagnosis was established and/or the findings altered subsequent clinical management. Results. Fifteen patients (9 male; mean age 58 ± 15 years) underwent bedside EUS without complications. EUS-FNA (median 4 passes; range 2–7) performed in 12 (80%) demonstrated a malignant mediastinal mass/lymph node (5), pancreatic abscess (1), excluded a pelvic abscess (1), established enlarged gastric folds as benign (1) and excluded malignancy in enlarged mediastinal (1) and porta hepatis adenopathy (1). In two patients, EUS-FNA failed to diagnose mediastinal histoplasmosis (1) and a hemorrhagic pancreatic pseudocyst (1). In three diagnostic exams without FNA, EUS correctly excluded choledocholithaisis (n = 1) and cholangiocarcinoma (1), and found gastric varices successfully thrombosed after previous cyanoacrylate injection (1). EUS was considered to have an impact in 13/15 (87%) patients. Conclusions. In this series, bedside EUS in critically ill patients was technically feasible, safe and had a major impact on the majority of patients

    Clinical Study Bedside Endoscopic Ultrasound in Critically Ill patients

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    Background. The aim of this study was to evaluate the role and impact of EUS in the management of critically ill patients. Methods. We retrospectively identified all patients at our institution over a 68-month period in whom bedside inpatient EUS was performed. EUS was considered to have a significant impact if a new diagnosis was established and/or the findings altered subsequent clinical management. Results. Fifteen patients (9 male; mean age 58 ± 15 years) underwent bedside EUS without complications. EUS-FNA (median 4 passes; range 2–7) performed in 12 (80%) demonstrated a malignant mediastinal mass/lymph node (5), pancreatic abscess (1), excluded a pelvic abscess (1), established enlarged gastric folds as benign (1) and excluded malignancy in enlarged mediastinal (1) and porta hepatis adenopathy (1). In two patients, EUS-FNA failed to diagnose mediastinal histoplasmosis (1) and a hemorrhagic pancreatic pseudocyst (1). In three diagnostic exams without FNA, EUS correctly excluded choledocholithaisis (n = 1) and cholangiocarcinoma (1), and found gastric varices successfully thrombosed after previous cyanoacrylate injection (1). EUS was considered to have an impact in 13/15 (87%) patients. Conclusions. In this series, bedside EUS in critically ill patients was technically feasible, safe and had a major impact on the majority of patients. 1

    Connexin-43 upregulation in micrometastases and tumor vasculature and its role in tumor cell attachment to pulmonary endothelium

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    <p>Abstract</p> <p>Background</p> <p>The modulation of gap junctional communication between tumor cells and between tumor and vascular endothelial cells during tumorigenesis and metastasis is complex. The notion of a role for loss of gap junctional intercellular communication in tumorigenesis and metastasis has been controversial. While some of the stages of tumorigenesis and metastasis, such as uncontrolled cell division and cellular detachment, would necessitate the loss of intercellular junctions, other stages, such as intravasation, endothelial attachment, and vascularization, likely require increased cell-cell contact. We hypothesized that, in this multi-stage scheme, connexin-43 is centrally involved as a cell adhesion molecule mediating metastatic tumor attachment to the pulmonary endothelium.</p> <p>Methods</p> <p>Tumor cell attachment to pulmonary vasculature, tumor growth, and connexin-43 expression was studied in metastatic lung tumor sections obtained after tail-vein injection into nude mice of syngeneic breast cancer cell lines, overexpressing wild type connexin-43 or dominant-negatively mutated connexin-43 proteins. High-resolution immunofluorescence microscopy and Western blot analysis was performed using a connexin-43 monoclonal antibody. Calcein Orange Red AM dye transfer by fluorescence imaging was used to evaluate the gap junction function.</p> <p>Results</p> <p>Adhesion of breast cancer cells to the pulmonary endothelium increased with cancer cells overexpressing connexin-43 and markedly decreased with cells expressing dominant-negative connexin-43. Upregulation of connexin-43 was observed in tumor cell-endothelial cell contact areas <it>in vitro </it>and <it>in vivo</it>, and in areas of intratumor blood vessels and in micrometastatic foci.</p> <p>Conclusion</p> <p>Connexin-43 facilitates metastatic 'homing' by increasing adhesion of cancer cells to the lung endothelial cells. The marked upregulation of connexin-43 in tumor cell-endothelial cell contact areas, whether in preexisting 'homing' vessels or in newly formed tumor vessels, suggests that connexin-43 can serve as a potential marker of micrometastases and tumor vasculature and that it may play a role in the early incorporation of endothelial cells into small tumors as seeds for vasculogenesis.</p

    Experimental and numerical investigation of multi-layered honeycomb sandwich composites for impact mechanics applications

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    This project aims to investigate the design of a multi-layered sandwich composite and its performance under impact loading conditions. An experimental and numerical assessment was performed to conclude the effect of increasing the layers of sandwich panels. Three specimens of four different sandwich panel configurations were manufactured to be tested. The skin of the sandwich panels comprises a twill carbon-reinforced epoxy resin, whereas the core consists of a 2D Nomex honeycomb core. The panels are then subjected to transverse impact loading to investigate their impact behaviour. These experimental results are then used to verify numerical models constructed in LS-Dyna. The models of the honeycomb-reinforced sandwich panels are investigated using MAT-054 and MAT-142 material cards in LS-Dyna to find the most economical computational approach. Finally, the energy absorption characteristics calculated during the experimental and numerical work are used to conclude the multi-layered sandwich composite's performance and provide design recommendations. The findings suggest that by increasing the core and shell numbers through the thickness of the panel, the specific energy absorption capability will increase

    Burning Mouth Syndrome, Relationships with Some Systemic Medications (A clinical study among an Iraqi sample)

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    Despite the numbers of studies upon burning symptoms in patients with clinically healthy appearance of the oral mucosa, as well as burning mouth syndrome (BMS) itself, they both remain still challenging subjects. The aim of this study was arranged to evaluate the effects of some systemic medication in the occurrence of BMS in relation to other etiological factors that may share in causing this disease in an Iraqi sample. Out of eighty, fifty patients (28 female and 22 males) were selected as a study group, all of them suffered from BMS, clinical and laboratory examinations in addition to previous diagnosis for the patients on the referral forma were depending on identifying the etiological causes for the BMS. This study revealed that antihypertensive and antidepressant medications were more affecting among this studied Iraqi sample with BMS than other etiological factor
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