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  • Publication . Article . Preprint . 2018
    Open Access English
    Authors: 
    Lu, Xuan; Cao, Yanbin; Chen, Zhenpeng; Liu, Xuanzhe;

    Emoji is becoming a ubiquitous language and gaining worldwide popularity in recent years including the field of software engineering (SE). As nonverbal cues, emojis are widely used in user understanding tasks such as sentiment analysis, but few work has been done to study emojis in SE scenarios. This paper presents a large scale empirical study on how GitHub users use emojis in development-related communications. We find that emojis are used by a considerable proportion of GitHub users. In comparison to Internet users, developers show interesting usage characteristics and have their own interpretation of the meanings of emojis. In addition, the usage of emojis reflects a positive and supportive culture of this community. Through a manual annotation task, we find that sentimental usage is a main intention of using emojis in issues, pull requests, and comments, while emojis are mainly used to emphasize important contents in README. These findings not only deepen our understanding about the culture of SE communities, but also provide implications on how to facilitate SE tasks with emojis such as sentiment analysis.

  • Open Access
    Authors: 
    Ahmad Fauzi Ismail; Mahesh Padaki; Nidal Hilal; Takeshi Matsuura; Woei Jye Lau;
    Publisher: Elsevier BV
    Country: United Kingdom

    This paper provides a review on the recent development of thin film composite (TFC) membrane, which has received increasing attention in the field of water desalination process. The development of new thin films and substrates, and the effect of additives are mostly focused in this review. In particular, nanotechnology has shown its impact on the development of TFC membranes by incorporating nanoparticles and nanofibers in the substrate as well as in the top thin film. The search for novel monomers and novel fabrication methods of thin film, modification of substrate, and optimization of operational conditions is also the topic of this review article. It still remains a challenge to produce high impact TFC membranes with antifouling and biofouling properties, chemical resistance, improved mechanical strength and thermal stability. For this purpose, further insights into the phase inversion and interfacial polymerization processes are necessary. Currently, it seems that there is no end in the near future for the further development of TFC membranes, which will be followed by the expansion of the scope of their applications in various chemical and biochemical industrial sectors.

  • Open Access
    Authors: 
    Elizabeth Bancroft; Elizabeth Page; Elena Castro; Hans Lilja; Andrew J. Vickers; Daniel Sjöberg; Melissa Assel; Christopher S. Foster; Gillian Mitchell; Kate Drew; +105 more
    Publisher: Elsevier BV
    Countries: Denmark, United Kingdom, Netherlands
    Project: NIH | Improving prostate cancer... (5R01CA175491-04), NIH | Prospective validation of... (5R01CA160816-02), NIH | RATIONAL DESIGN OF PROSTA... (5P50CA092629-10)

    Background Men with germline breast cancer 1, early onset (BRCA1) or breast cancer 2, early onset (BRCA2) gene mutations have a higher risk of developing prostate cancer (PCa) than noncarriers. IMPACT (Identification of Men with a genetic predisposition to ProstAte Cancer: Targeted screening in BRCA1/2 mutation carriers and controls) is an international consortium of 62 centres in 20 countries evaluating the use of targeted PCa screening in men with BRCA1/2 mutations. Objective To report the first year's screening results for all men at enrolment in the study. Design, setting and participants We recruited men aged 40–69 yr with germline BRCA1/2 mutations and a control group of men who have tested negative for a pathogenic BRCA1 or BRCA2 mutation known to be present in their families. All men underwent prostate-specific antigen (PSA) testing at enrolment, and those men with PSA >3 ng/ml were offered prostate biopsy. Outcome measurements and statistical analysis PSA levels, PCa incidence, and tumour characteristics were evaluated. The Fisher exact test was used to compare the number of PCa cases among groups and the differences among disease types. Results and limitations We recruited 2481 men (791 BRCA1 carriers, 531 BRCA1 controls; 731 BRCA2 carriers, 428 BRCA2 controls). A total of 199 men (8%) presented with PSA >3.0 ng/ml, 162 biopsies were performed, and 59 PCas were diagnosed (18 BRCA1 carriers, 10 BRCA1 controls; 24 BRCA2 carriers, 7 BRCA2 controls); 66% of the tumours were classified as intermediate- or high-risk disease. The positive predictive value (PPV) for biopsy using a PSA threshold of 3.0 ng/ml in BRCA2 mutation carriers was 48%—double the PPV reported in population screening studies. A significant difference in detecting intermediate- or high-risk disease was observed in BRCA2 carriers. Ninety-five percent of the men were white, thus the results cannot be generalised to all ethnic groups. Conclusions The IMPACT screening network will be useful for targeted PCa screening studies in men with germline genetic risk variants as they are discovered. These preliminary results support the use of targeted PSA screening based on BRCA genotype and show that this screening yields a high proportion of aggressive disease. Patient summary In this report, we demonstrate that germline genetic markers can be used to identify men at higher risk of prostate cancer. Targeting screening at these men resulted in the identification of tumours that were more likely to require treatment. Take Home Message This report demonstrates that germline genetic markers can be used to identify men at higher risk of prostate cancer. Targeting screening at these higher-risk men resulted in the identification of tumours that were more likely to require treatment.

  • Closed Access English
    Authors: 
    Javier Cortes; David W. Cescon; Hope S. Rugo; Zbigniew Nowecki; Seock-Ah Im; Mastura Md Yusof; Carlos Gallardo; Oleg Lipatov; Carlos H. Barrios; Esther Holgado; +190 more
    Publisher: Lancet Publishing Group
    Country: Turkey

    JC reports personal fees and research funding paid to his institution from Roche, AstraZeneca, Merck Sharp & Dohme, and Eisai; personal fees from Celgene, Cellestia, Biothera Pharmaceutical, Merus, Seattle Genetics, Daiichi Sankyo, Erytech, Athenex, Polyphor, Lilly, Servier, GlaxoSmithKline, Leuko, Bioasis, Clovis Oncology, Boehringer Ingelheim, Kyowa Kirin, Novartis, Pfizer, Samsung Bioepis; research funding paid to his institution from Ariad Pharmaceuticals, Bayer Healthcare, F Hoffman-La Roche, Guardanth Health, Piqur Therapeutics, Puma C, and Queen Mary University of London, outside the submitted work. In addition, JC has a MedSIR patent pending. DWC reports research support from Merck during the conduct of the study; research support paid to his institution from Merck, Pfizer, and GlaxoSmithKline; personal fees from Merck, Roche–Genentech, AstraZeneca, GlaxoSmithKline, Novartis, Pfizer, Puma, Agenda, Exact Sciences, and Dynamo Therapeutics, outside the submitted work. In addition, DWC has a Biomarkers of TTK inhibitors patent pending. HSR reports funding for sponsored studies paid to the University of California San Francisco from Pfizer, Novartis, Lilly, Roche–Genentech, Macrogenics, OBI, Merck, Eisai, Immunomedics, Daiichi Sankyo, Seattle Genetics, and Odonate; travel support for educational meetings from Daiichi Sankyo, Mylan, Pfizer, Merck, AstraZeneca, Novartis, and Macrogenics; and consulting fees from Samsung and Puma, outside the submitted work. S-AI reports grants from AstraZeneca, Eisai, Pfizer, Roche, and Daewoong; an advisory role for AstraZeneca, Amgen, Eisai, Hanmi, Novartis, Lily, MedPacto, Pfizer, and Roche; and travel expenses for presentation from Novartis, outside the submitted work. CG reports Advisory Board fees from Merck Sharp & Dohme and Roche; and speaker's bureau fees from Bristol Myers Squibb and AstraZeneca, outside the submitted work. CHB reports grants and fees from Merck Sharp & Dohme for clinical research consulting during the conduct of the study; consulting–advisory role fees from Boehringer Ingelheim, GlaxoSmithKline, and Bayer; consulting–advisory role fees and grants for clinical research from Novartis, Pfizer, Roche–Genentech, Eisai, Merck Sharp & Dohme, and AstraZeneca; grants for clinical research from Abbvie, Amgen, Astellas Pharma, Bristol Myers Squibb, Celgene, Covance, Lilly, Medication, Merck Serono, and PharmaMar; grants for academic research projects from CPO, Pontificia Universidade Católica do Rio Grande do Sul, Latin American Cooperative Oncology Group, Grupo Brasileiro Estudos Câncer Mama, and Instituto Nacional de Câncer-Brazil, outside the submitted work. HI reports a grant from Merck Sharp & Dohme during the conduct of the study; honoraria and consulting fees from Novartis, AstraZeneca, Pfizer, Lilly, Daiichi Sankyo, Eisai, and Chugai; and a grant from Chugai, outside the submitted work. NM reports honoraria and research funding paid to his institution from Chugai, AstraZeneca, Pfizer, Eli-Lilly, Eisai, Takeda, Kyowa-Kirin, Merck Sharp & Dohme, Novartis, and Daiichi Sankyo, outside the submitted work. EG reports non-financial support from Merck Sharp & Dohme during the conduct of the study; honoraria, consulting–advisory fees and meeting support from Novartis, Roche, Bristol Myers Squibb, and Pfizer; and honoraria from AstraZeneca and Astellas, outside the submitted work. SL reports research funding or consulting fees paid to her institution from Bristol Myers Squibb, Roche–Genentech, Puma Biotechnology, Pfizer, Seattle Genetics, Novartis, Merck Sharp & Dohme, Eli Lilly, Aduro Biotech, GI Therapeutics, AstraZeneca, and GlaxoSmithKline; and non-remunerated consultancy for Bristol Myers Squibb, Roche–Genentech, Pfizer, Seattle Genetics, Novartis, Merck Sharp & Dohme, and AstraZeneca, outside the submitted work. In addition, SL is supported by the National Breast Cancer Foundation of Australia Endowed Chair and the Breast Cancer Research Foundation, New York. ZG, JZ, GA, and VK are employees of Merck Sharp & Dohme and own stock or stock options in Merck. PS reports consultancy fees from Pfizer, AstraZeneca, Novartis, Roche, Merck Sharp & Dohme, Boehringer Ingelheim, Bayer, Eisai, Celgene, and Puma; consultancy fees to his spouse from Genentech and Roche; and grants or funding to his institution from Roche, Genentech, Oncogenex, Novartis, Astellas, and AstraZeneca, outside the submitted work. All other authors declare no competing interests. Background: Pembrolizumab monotherapy showed durable antitumour activity and manageable safety in patients with metastatic triple-negative breast cancer. We aimed to examine whether the addition of pembrolizumab would enhance the antitumour activity of chemotherapy in patients with metastatic triple-negative breast cancer. Methods: In this randomised, placebo-controlled, double-blind, phase 3 trial, done in 209 sites in 29 countries, we randomly assigned patients 2:1 with untreated locally recurrent inoperable or metastatic triple-negative breast cancer using a block method (block size of six) and an interactive voice-response system with integrated web-response to pembrolizumab (200 mg) every 3 weeks plus chemotherapy (nab-paclitaxel; paclitaxel; or gemcitabine plus carboplatin) or placebo plus chemotherapy. Randomisation was stratified by type of on-study chemotherapy (taxane or gemcitabine–carboplatin), PD-L1 expression at baseline (combined positive score [CPS] ?1 or <1), and previous treatment with the same class of chemotherapy in the neoadjuvant or adjuvant setting (yes or no). Eligibility criteria included age at least 18 years, centrally confirmed triple-negative breast cancer; at least one measurable lesion; provision of a newly obtained tumour sample for determination of triple-negative breast cancer status and PD-L1 status by immunohistochemistry at a central laboratory; an Eastern Cooperative Oncology Group performance status score 0 or 1; and adequate organ function. The sponsor, investigators, other study site staff (except for the unmasked pharmacist), and patients were masked to pembrolizumab versus saline placebo administration. In addition, the sponsor, the investigators, other study site staff, and patients were masked to patient-level tumour PD-L1 biomarker results. Dual primary efficacy endpoints were progression-free survival and overall survival assessed in the PD-L1 CPS of 10 or more, CPS of 1 or more, and intention-to-treat populations. The definitive assessment of progression-free survival was done at this interim analysis; follow-up to assess overall survival is continuing. For progression-free survival, a hierarchical testing strategy was used, such that testing was done first in patients with CPS of 10 or more (prespecified statistical criterion was ?=0·00411 at this interim analysis), then in patients with CPS of 1 or more (?=0·00111 at this interim analysis, with partial alpha from progression-free survival in patients with CPS of 10 or more passed over), and finally in the intention-to-treat population (?=0·00111 at this interim analysis). This study is registered with ClinicalTrials.gov, NCT02819518, and is ongoing. Findings: Between Jan 9, 2017, and June 12, 2018, of 1372 patients screened, 847 were randomly assigned to treatment, with 566 patients in the pembrolizumab–chemotherapy group and 281 patients in the placebo–chemotherapy group. At the second interim analysis (data cutoff, Dec 11, 2019), median follow-up was 25·9 months (IQR 22·8–29·9) in the pembrolizumab–chemotherapy group and 26·3 months (22·7–29·7) in the placebo–chemotherapy group. Among patients with CPS of 10 or more, median progression-free survival was 9·7 months with pembrolizumab–chemotherapy and 5·6 months with placebo–chemotherapy (hazard ratio [HR] for progression or death, 0·65, 95% CI 0·49–0·86; one-sided p=0·0012 [primary objective met]). Median progression-free survival was 7·6 and 5·6 months (HR, 0·74, 0·61–0·90; one-sided p=0·0014 [not significant]) among patients with CPS of 1 or more and 7·5 and 5·6 months (HR, 0·82, 0·69–0·97 [not tested]) among the intention-to-treat population. The pembrolizumab treatment effect increased with PD-L1 enrichment. Grade 3–5 treatment-related adverse event rates were 68% in the pembrolizumab–chemotherapy group and 67% in the placebo–chemotherapy group, including death in <1% in the pembrolizumab–chemotherapy group and 0% in the placebo–chemotherapy group. Interpretation: Pembrolizumab–chemotherapy showed a significant and clinically meaningful improvement in progression-free survival versus placebo–chemotherapy among patients with metastatic triple-negative breast cancer with CPS of 10 or more. These findings suggest a role for the addition of pembrolizumab to standard chemotherapy for the first-line treatment of metastatic triple-negative breast cancer. Funding: Merck Sharp & Dohme Corp, a subsidiary of Merck & Co, Inc. © 2020 Elsevier Ltd The authors thank the patients, their families and caregivers for participating in this trial, all of the investigators and site personnel, and the following employees of Merck Sharp & Dohme: Wilbur Pan, Deborah Card, Eleanor Readinger, Shana Hamm, Roger Maxwell, and Krystal Bourdon, for collection of data, supervision of research, provision of study materials or patients or administrative or logistical support; Aline Galvao, for collection of data, supervision of research, administrative or logistical support, and review of imaging data related to the primary end point; Donna Letizia, for collection of data and imaging expertise; Jennifer Kimmel, for study management; Mercedes Bustamante, for data collection and management; Xuan Zhou and Madhusudhan Reddy Papasani, for statistical expertise; Christine McCrary Sisk, for medical writing and editorial assistance; and Joseph C Naggar and Michele McColgan, for administrative or logistical support. Breast Cancer Research Foundation, BCRF; Pfizer; AstraZeneca; Merck; Roche; Samsung; Merck Sharp and Dohme, MSD; Eisai

  • Publication . Article . 2010
    Open Access
    Authors: 
    Rosanna W. Peeling; Harvey Artsob; José L. Pelegrino; Philippe Buchy; Mary Jane Cardosa; Shamala Devi; Delia Enria; Jeremy Farrar; Duane J. Gubler; María G. Guzmán; +9 more

    Dengue is an arthropod-borne flavivirus that comprises four distinct serotypes (DEN-1, DEN-2, DEN-3 and DEN-4) that constitute an antigenic complex of the genus flavivirus, family Flaviviridae. Infection by one serotype induces life-long immunity against reinfection by the same serotype, but only transient and partial protection against infection with the other serotypes1,2. Dengue virus infections can result in a range of clinical manifestations from asymp tomatic infection to dengue fever (DF) and the severe disease dengue haemorrhagic fever/dengue shock syndrome (DHF/ DSS). Most dengue infections are asymptomatic or cause mild symptoms, which are characterized by undifferentiated fever with or without rash. Typical DF is characterized by high fever, severe headache, myalgia, arthralgia, retro-orbital pain and maculopapular rash. Some patients show petechiae, bruising or thrombocytopenia. The clinical presentation of acute dengue infection is non-specific but 5–10% of patients progress to severe DHF/DSS, which can result in death if it is not managed appropriately. Plasma extravasation is the main pathophysiological finding of DHF/ DSS, which differentiates it from DF. DHF/ DSS is characterized by high fever, bleeding, thrombocytopenia and haemoconcentration (an increase in the concentration of blood cells as a result of fluid loss). Approximately 3–4 days after the onset of fever, patients can present with petechiae, rash, epistaxis, and gingival and gastrointestinal bleeding. Pleural effusion and ascites are common. Some patients develop circulatory failure (DSS), presenting with a weak and fast pulse, narrowing of pulse pressure or hypotension, cold and moist skin and altered mental state. Although there are no specific antiviral treatments for dengue infection, patients usually recover when the need for fluid management is identified early and electrolytes are administered3. It has been proposed that the classification of dengue disease should be simplified as severe and non-severe dengue. This simplified classification would make patient management and surveillance easier4. There is a need for specific, inexpensive dengue diagnostic tests that can be used for clinical management, surveillance and outbreak investigations and would permit early intervention to treat patients and prevent or control epidemics. Progress is being made in primary prevention, with several candidate dengue vaccines in late phases of development as well as improved vector control measures. Additionally, new techniques for the early detection of severe disease such as the use of biomarkers have the potential to decrease morbidity and

  • Open Access English
    Authors: 
    Ondřej Kaplan; Jana Zarubova; Barbora Mikulová; Elena Filova; Jiřina Bártová; Lucie Bacakova; Eduard Brynda;
    Publisher: Public Library of Science (PLoS)

    We describe the production of a highly-active mutant VEGF variant, α2-PI1-8-VEGF121, which contains a substrate sequence for factor XIIIa at the aminoterminus designed for incorporation into a fibrin gel. The α2-PI1-8-VEGF121 gene was synthesized, cloned into a pET-32a(+) vector and expressed in Escherichia coli Origami B (DE3) host cells. To increase the protein folding and the solubility, the resulting thioredoxin-α2-PI1-8-VEGF121 fusion protein was co-expressed with recombinant molecular chaperones GroES/EL encoded by independent plasmid pGro7. The fusion protein was purified from the soluble fraction of cytoplasmic proteins using affinity chromatography. After cleavage of the thioredoxin fusion part with thrombin, the target protein was purified by a second round of affinity chromatography. The yield of purified α2-PI1-8-VEGF121 was 1.4 mg per liter of the cell culture. The α2-PI1-8-VEGF121 expressed in this work increased the proliferation of endothelial cells 3.9-8.7 times in comparison with commercially-available recombinant VEGF121. This very high mitogenic activity may be caused by co-expression of the growth factor with molecular chaperones not previously used in VEGF production. At the same time, α2-PI1-8-VEGF121 did not elicit considerable inflammatory activation of human endothelial HUVEC cells and human monocyte-like THP-1 cells.

  • Closed Access
    Authors: 
    Fatemeh Korminouri; Masoud Rahbari-Sisakht; Dipak Rana; Takeshi Matsuura; Ahmad Fauzi Ismail;
    Publisher: Elsevier BV

    Abstract Surface modified polyvinylidene fluoride (PVDF) hollow fiber membranes (HFMs) were spun via dry–wet spinning technique at different air–gap lengths (0–20 cm). The morphology of prepared membranes was evaluated by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Membranes were also characterized in terms of gas permeation, overall porosity, collapsing pressure, critical water entry pressure (CEPw) and contact angle. To determine the CO 2 absorption flux of HFMs, a gas–liquid membrane contactor system was used. Experimental results of this study revealed that by increasing the air–gap distance from 0 to 20 cm, wetting resistance and contact angle of fabricated membranes increased due to enhancement of membrane surface hydrophobicity. The highest helium (He) permeation was achieved for the spun fiber at the air–gap of 10 cm. From CO 2 absorption experiment it was found that the hollow fiber spun at the air–gap of 10 cm had the maximum CO 2 absorption flux of 1.41 × 10 −3 mol/m 2 s at the absorbent flow rate of 300 ml/min, which was significantly higher than CO 2 absorption flux obtained by other researchers. It was also found that both highest He gas permeance and CO 2 absorption flux were controlled by the surface porosity of the hollow fiber due to the maximum values obtained. Thus, the choice of an appropriate air–gap distance for fabrication of surface modified membranes was found to be a promising method to improve CO 2 removal in membrane contactor systems.

  • Open Access
    Authors: 
    Maria Skaalum Petersen; Cecilie Bo Hansen; Marnar Fríðheim Kristiansen; Jógvan Páll Fjallsbak; Sólrun Larsen; Jóhanna Ljósá Hansen; Ida Jarlhelt; Laura Pérez-Alós; Bjarni á Steig; Debes Hammershaimb Christiansen; +6 more
    Publisher: Cold Spring Harbor Laboratory

    AbstractOnly a few studies have assessed the long-term duration of the humoral immune response against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).In this nationwide longitudinal study from the Faroe Islands with close to full participation of all individuals on the Islands with PCR confirmed COVID-19 during the two waves of infections in the spring and autumn 2020 (n=172 & n=233), samples were drawn at three longitudinal time points (3, 7 and 12 months and 1, 3 and 7 months after disease onset, respectively).Serum was analyzed with a direct quantitative IgG antibody binding ELISA to detect anti–SARS-CoV-2 spike RBD antibodies and a commercially available qualitative sandwich RBD ELISA kit measuring total antibody binding.The seropositive rate in the convalescent individuals was above 95 % at all sampling time points for both assays. There was an overall decline in IgG titers over time in both waves (p < 0.001). Pairwise comparison showed that IgG declined significantly from the first sample until approximately 7 months in both waves (p < 0.001). After that, the antibody level still declined significantly (p < 0.001), but decelerated with an altered slope remaining fairly stable from 7 months to 12 months after infection. Interestingly, the IgG titers followed a U-shaped curve with higher antibody levels among the oldest (67+) and the youngest (0– 17) age groups compared to intermediate groups (p < 0.001).Our results indicate that COVID-19 convalescent individuals are likely to be protected from reinfection up to 12 months after symptom onset and maybe even longer. We believe our results can add to the understanding of natural immunity and the expected durability of SARS-CoV-2 vaccine immune responses.

  • Open Access
    Authors: 
    Alexander K. C. Leung; Joseph M. Lam; Kin Fon Leong;
    Publisher: Bentham Science Publishers Ltd.

    Background: The diagnosis of solitary cutaneous mastocytoma is mainly clinical, based on lesion morphology, the presence of a positive Darier sign, and the absence of systemic involvement. Knowledge of this condition is important so that an accurate diagnosis can be made. Objective: To familiarize physicians with the clinical manifestations, diagnosis, evaluation, and management of a solitary cutaneous mastocytoma. Methods: A PubMed search was completed in Clinical Queries using the key term "solitary cutaneous mastocytoma". The search strategy included meta-analyses, randomized controlled trials, clinical trials, observational studies, and reviews. Only papers published in English language were included. The information retrieved from the above search was used in the compilation of the present article. Results: Typically, a solitary cutaneous mastocytoma presents as an indurated, erythematous, yellow- brown or reddish-brown macule, papule, plaque or nodule, usually measuring up to 5 cm in diameter. The lesion often has a peau d'orange appearance and a leathery or rubbery consistency. A solitary cutaneous mastocytoma may urticate spontaneously or when stroked or rubbed (Darier sign). Organomegaly and lymphadenopathy are characteristically absent. The majority of patients with skin lesions that erupt within the first two years of life have spontaneous resolution of the lesions before puberty. Treatment is mainly symptomatic. Reassurance and avoidance of triggering factors suffice in most cases. Conclusion: The diagnosis is mainly clinical, based on the morphology of the lesion, the presence of a positive Darier sign, and the absence of systemic involvement. A skin biopsy is usually not necessary unless the diagnosis is in doubt.

  • Open Access English
    Authors: 
    Ghasan Fahim Huseien; Mohammad Ismail; Nur Hafizah A. Khalid; Mohd Warid Hussin; Jahangir Mirza;
    Publisher: Elsevier

    This paper presents the solution molarity dependent microstructures and mechanical properties of multi-blend geopolymer mortars (GPMs). Geopolymer mortars were cured at ambient temperature under varying concentration (from 2 to 16 M) of sodium hydroxide (NH) solution. GPMs are by conducting mechanical tests such as compressive, split tensile and flexural strengths and characterised by microstructural studies, such as X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray spectroscopy (EDS). The effect of Na2O, H2O content, solution modulus (SiO2:Na2O) and Na2O:Al2O3 on GPMs strength were determined. The flow ability and setting time of such GPMs found to decrease linearly with increasing alkali concentration. Conversely, the GPMs comprehensive, split tensile and flexural strengths and the density are enhanced with increasing alkali concentration. Samples activated with 12 M NH solution are most strongly affected by silica dissolution. Furthermore, the ratio of (Na2O:Al2O3) was demonstrated to influence the compressive strength significantly and the (Na2O:Al2O3 = 0.84) presented the optimum strength. Keywords: Geopolymer, Alkali solution molarity, Compressive strength, Microstructure

Include:
5,254 Research products, page 1 of 526
  • Publication . Article . Preprint . 2018
    Open Access English
    Authors: 
    Lu, Xuan; Cao, Yanbin; Chen, Zhenpeng; Liu, Xuanzhe;

    Emoji is becoming a ubiquitous language and gaining worldwide popularity in recent years including the field of software engineering (SE). As nonverbal cues, emojis are widely used in user understanding tasks such as sentiment analysis, but few work has been done to study emojis in SE scenarios. This paper presents a large scale empirical study on how GitHub users use emojis in development-related communications. We find that emojis are used by a considerable proportion of GitHub users. In comparison to Internet users, developers show interesting usage characteristics and have their own interpretation of the meanings of emojis. In addition, the usage of emojis reflects a positive and supportive culture of this community. Through a manual annotation task, we find that sentimental usage is a main intention of using emojis in issues, pull requests, and comments, while emojis are mainly used to emphasize important contents in README. These findings not only deepen our understanding about the culture of SE communities, but also provide implications on how to facilitate SE tasks with emojis such as sentiment analysis.

  • Open Access
    Authors: 
    Ahmad Fauzi Ismail; Mahesh Padaki; Nidal Hilal; Takeshi Matsuura; Woei Jye Lau;
    Publisher: Elsevier BV
    Country: United Kingdom

    This paper provides a review on the recent development of thin film composite (TFC) membrane, which has received increasing attention in the field of water desalination process. The development of new thin films and substrates, and the effect of additives are mostly focused in this review. In particular, nanotechnology has shown its impact on the development of TFC membranes by incorporating nanoparticles and nanofibers in the substrate as well as in the top thin film. The search for novel monomers and novel fabrication methods of thin film, modification of substrate, and optimization of operational conditions is also the topic of this review article. It still remains a challenge to produce high impact TFC membranes with antifouling and biofouling properties, chemical resistance, improved mechanical strength and thermal stability. For this purpose, further insights into the phase inversion and interfacial polymerization processes are necessary. Currently, it seems that there is no end in the near future for the further development of TFC membranes, which will be followed by the expansion of the scope of their applications in various chemical and biochemical industrial sectors.

  • Open Access
    Authors: 
    Elizabeth Bancroft; Elizabeth Page; Elena Castro; Hans Lilja; Andrew J. Vickers; Daniel Sjöberg; Melissa Assel; Christopher S. Foster; Gillian Mitchell; Kate Drew; +105 more
    Publisher: Elsevier BV
    Countries: Denmark, United Kingdom, Netherlands
    Project: NIH | Improving prostate cancer... (5R01CA175491-04), NIH | Prospective validation of... (5R01CA160816-02), NIH | RATIONAL DESIGN OF PROSTA... (5P50CA092629-10)

    Background Men with germline breast cancer 1, early onset (BRCA1) or breast cancer 2, early onset (BRCA2) gene mutations have a higher risk of developing prostate cancer (PCa) than noncarriers. IMPACT (Identification of Men with a genetic predisposition to ProstAte Cancer: Targeted screening in BRCA1/2 mutation carriers and controls) is an international consortium of 62 centres in 20 countries evaluating the use of targeted PCa screening in men with BRCA1/2 mutations. Objective To report the first year's screening results for all men at enrolment in the study. Design, setting and participants We recruited men aged 40–69 yr with germline BRCA1/2 mutations and a control group of men who have tested negative for a pathogenic BRCA1 or BRCA2 mutation known to be present in their families. All men underwent prostate-specific antigen (PSA) testing at enrolment, and those men with PSA >3 ng/ml were offered prostate biopsy. Outcome measurements and statistical analysis PSA levels, PCa incidence, and tumour characteristics were evaluated. The Fisher exact test was used to compare the number of PCa cases among groups and the differences among disease types. Results and limitations We recruited 2481 men (791 BRCA1 carriers, 531 BRCA1 controls; 731 BRCA2 carriers, 428 BRCA2 controls). A total of 199 men (8%) presented with PSA >3.0 ng/ml, 162 biopsies were performed, and 59 PCas were diagnosed (18 BRCA1 carriers, 10 BRCA1 controls; 24 BRCA2 carriers, 7 BRCA2 controls); 66% of the tumours were classified as intermediate- or high-risk disease. The positive predictive value (PPV) for biopsy using a PSA threshold of 3.0 ng/ml in BRCA2 mutation carriers was 48%—double the PPV reported in population screening studies. A significant difference in detecting intermediate- or high-risk disease was observed in BRCA2 carriers. Ninety-five percent of the men were white, thus the results cannot be generalised to all ethnic groups. Conclusions The IMPACT screening network will be useful for targeted PCa screening studies in men with germline genetic risk variants as they are discovered. These preliminary results support the use of targeted PSA screening based on BRCA genotype and show that this screening yields a high proportion of aggressive disease. Patient summary In this report, we demonstrate that germline genetic markers can be used to identify men at higher risk of prostate cancer. Targeting screening at these men resulted in the identification of tumours that were more likely to require treatment. Take Home Message This report demonstrates that germline genetic markers can be used to identify men at higher risk of prostate cancer. Targeting screening at these higher-risk men resulted in the identification of tumours that were more likely to require treatment.

  • Closed Access English
    Authors: 
    Javier Cortes; David W. Cescon; Hope S. Rugo; Zbigniew Nowecki; Seock-Ah Im; Mastura Md Yusof; Carlos Gallardo; Oleg Lipatov; Carlos H. Barrios; Esther Holgado; +190 more
    Publisher: Lancet Publishing Group
    Country: Turkey

    JC reports personal fees and research funding paid to his institution from Roche, AstraZeneca, Merck Sharp & Dohme, and Eisai; personal fees from Celgene, Cellestia, Biothera Pharmaceutical, Merus, Seattle Genetics, Daiichi Sankyo, Erytech, Athenex, Polyphor, Lilly, Servier, GlaxoSmithKline, Leuko, Bioasis, Clovis Oncology, Boehringer Ingelheim, Kyowa Kirin, Novartis, Pfizer, Samsung Bioepis; research funding paid to his institution from Ariad Pharmaceuticals, Bayer Healthcare, F Hoffman-La Roche, Guardanth Health, Piqur Therapeutics, Puma C, and Queen Mary University of London, outside the submitted work. In addition, JC has a MedSIR patent pending. DWC reports research support from Merck during the conduct of the study; research support paid to his institution from Merck, Pfizer, and GlaxoSmithKline; personal fees from Merck, Roche–Genentech, AstraZeneca, GlaxoSmithKline, Novartis, Pfizer, Puma, Agenda, Exact Sciences, and Dynamo Therapeutics, outside the submitted work. In addition, DWC has a Biomarkers of TTK inhibitors patent pending. HSR reports funding for sponsored studies paid to the University of California San Francisco from Pfizer, Novartis, Lilly, Roche–Genentech, Macrogenics, OBI, Merck, Eisai, Immunomedics, Daiichi Sankyo, Seattle Genetics, and Odonate; travel support for educational meetings from Daiichi Sankyo, Mylan, Pfizer, Merck, AstraZeneca, Novartis, and Macrogenics; and consulting fees from Samsung and Puma, outside the submitted work. S-AI reports grants from AstraZeneca, Eisai, Pfizer, Roche, and Daewoong; an advisory role for AstraZeneca, Amgen, Eisai, Hanmi, Novartis, Lily, MedPacto, Pfizer, and Roche; and travel expenses for presentation from Novartis, outside the submitted work. CG reports Advisory Board fees from Merck Sharp & Dohme and Roche; and speaker's bureau fees from Bristol Myers Squibb and AstraZeneca, outside the submitted work. CHB reports grants and fees from Merck Sharp & Dohme for clinical research consulting during the conduct of the study; consulting–advisory role fees from Boehringer Ingelheim, GlaxoSmithKline, and Bayer; consulting–advisory role fees and grants for clinical research from Novartis, Pfizer, Roche–Genentech, Eisai, Merck Sharp & Dohme, and AstraZeneca; grants for clinical research from Abbvie, Amgen, Astellas Pharma, Bristol Myers Squibb, Celgene, Covance, Lilly, Medication, Merck Serono, and PharmaMar; grants for academic research projects from CPO, Pontificia Universidade Católica do Rio Grande do Sul, Latin American Cooperative Oncology Group, Grupo Brasileiro Estudos Câncer Mama, and Instituto Nacional de Câncer-Brazil, outside the submitted work. HI reports a grant from Merck Sharp & Dohme during the conduct of the study; honoraria and consulting fees from Novartis, AstraZeneca, Pfizer, Lilly, Daiichi Sankyo, Eisai, and Chugai; and a grant from Chugai, outside the submitted work. NM reports honoraria and research funding paid to his institution from Chugai, AstraZeneca, Pfizer, Eli-Lilly, Eisai, Takeda, Kyowa-Kirin, Merck Sharp & Dohme, Novartis, and Daiichi Sankyo, outside the submitted work. EG reports non-financial support from Merck Sharp & Dohme during the conduct of the study; honoraria, consulting–advisory fees and meeting support from Novartis, Roche, Bristol Myers Squibb, and Pfizer; and honoraria from AstraZeneca and Astellas, outside the submitted work. SL reports research funding or consulting fees paid to her institution from Bristol Myers Squibb, Roche–Genentech, Puma Biotechnology, Pfizer, Seattle Genetics, Novartis, Merck Sharp & Dohme, Eli Lilly, Aduro Biotech, GI Therapeutics, AstraZeneca, and GlaxoSmithKline; and non-remunerated consultancy for Bristol Myers Squibb, Roche–Genentech, Pfizer, Seattle Genetics, Novartis, Merck Sharp & Dohme, and AstraZeneca, outside the submitted work. In addition, SL is supported by the National Breast Cancer Foundation of Australia Endowed Chair and the Breast Cancer Research Foundation, New York. ZG, JZ, GA, and VK are employees of Merck Sharp & Dohme and own stock or stock options in Merck. PS reports consultancy fees from Pfizer, AstraZeneca, Novartis, Roche, Merck Sharp & Dohme, Boehringer Ingelheim, Bayer, Eisai, Celgene, and Puma; consultancy fees to his spouse from Genentech and Roche; and grants or funding to his institution from Roche, Genentech, Oncogenex, Novartis, Astellas, and AstraZeneca, outside the submitted work. All other authors declare no competing interests. Background: Pembrolizumab monotherapy showed durable antitumour activity and manageable safety in patients with metastatic triple-negative breast cancer. We aimed to examine whether the addition of pembrolizumab would enhance the antitumour activity of chemotherapy in patients with metastatic triple-negative breast cancer. Methods: In this randomised, placebo-controlled, double-blind, phase 3 trial, done in 209 sites in 29 countries, we randomly assigned patients 2:1 with untreated locally recurrent inoperable or metastatic triple-negative breast cancer using a block method (block size of six) and an interactive voice-response system with integrated web-response to pembrolizumab (200 mg) every 3 weeks plus chemotherapy (nab-paclitaxel; paclitaxel; or gemcitabine plus carboplatin) or placebo plus chemotherapy. Randomisation was stratified by type of on-study chemotherapy (taxane or gemcitabine–carboplatin), PD-L1 expression at baseline (combined positive score [CPS] ?1 or <1), and previous treatment with the same class of chemotherapy in the neoadjuvant or adjuvant setting (yes or no). Eligibility criteria included age at least 18 years, centrally confirmed triple-negative breast cancer; at least one measurable lesion; provision of a newly obtained tumour sample for determination of triple-negative breast cancer status and PD-L1 status by immunohistochemistry at a central laboratory; an Eastern Cooperative Oncology Group performance status score 0 or 1; and adequate organ function. The sponsor, investigators, other study site staff (except for the unmasked pharmacist), and patients were masked to pembrolizumab versus saline placebo administration. In addition, the sponsor, the investigators, other study site staff, and patients were masked to patient-level tumour PD-L1 biomarker results. Dual primary efficacy endpoints were progression-free survival and overall survival assessed in the PD-L1 CPS of 10 or more, CPS of 1 or more, and intention-to-treat populations. The definitive assessment of progression-free survival was done at this interim analysis; follow-up to assess overall survival is continuing. For progression-free survival, a hierarchical testing strategy was used, such that testing was done first in patients with CPS of 10 or more (prespecified statistical criterion was ?=0·00411 at this interim analysis), then in patients with CPS of 1 or more (?=0·00111 at this interim analysis, with partial alpha from progression-free survival in patients with CPS of 10 or more passed over), and finally in the intention-to-treat population (?=0·00111 at this interim analysis). This study is registered with ClinicalTrials.gov, NCT02819518, and is ongoing. Findings: Between Jan 9, 2017, and June 12, 2018, of 1372 patients screened, 847 were randomly assigned to treatment, with 566 patients in the pembrolizumab–chemotherapy group and 281 patients in the placebo–chemotherapy group. At the second interim analysis (data cutoff, Dec 11, 2019), median follow-up was 25·9 months (IQR 22·8–29·9) in the pembrolizumab–chemotherapy group and 26·3 months (22·7–29·7) in the placebo–chemotherapy group. Among patients with CPS of 10 or more, median progression-free survival was 9·7 months with pembrolizumab–chemotherapy and 5·6 months with placebo–chemotherapy (hazard ratio [HR] for progression or death, 0·65, 95% CI 0·49–0·86; one-sided p=0·0012 [primary objective met]). Median progression-free survival was 7·6 and 5·6 months (HR, 0·74, 0·61–0·90; one-sided p=0·0014 [not significant]) among patients with CPS of 1 or more and 7·5 and 5·6 months (HR, 0·82, 0·69–0·97 [not tested]) among the intention-to-treat population. The pembrolizumab treatment effect increased with PD-L1 enrichment. Grade 3–5 treatment-related adverse event rates were 68% in the pembrolizumab–chemotherapy group and 67% in the placebo–chemotherapy group, including death in <1% in the pembrolizumab–chemotherapy group and 0% in the placebo–chemotherapy group. Interpretation: Pembrolizumab–chemotherapy showed a significant and clinically meaningful improvement in progression-free survival versus placebo–chemotherapy among patients with metastatic triple-negative breast cancer with CPS of 10 or more. These findings suggest a role for the addition of pembrolizumab to standard chemotherapy for the first-line treatment of metastatic triple-negative breast cancer. Funding: Merck Sharp & Dohme Corp, a subsidiary of Merck & Co, Inc. © 2020 Elsevier Ltd The authors thank the patients, their families and caregivers for participating in this trial, all of the investigators and site personnel, and the following employees of Merck Sharp & Dohme: Wilbur Pan, Deborah Card, Eleanor Readinger, Shana Hamm, Roger Maxwell, and Krystal Bourdon, for collection of data, supervision of research, provision of study materials or patients or administrative or logistical support; Aline Galvao, for collection of data, supervision of research, administrative or logistical support, and review of imaging data related to the primary end point; Donna Letizia, for collection of data and imaging expertise; Jennifer Kimmel, for study management; Mercedes Bustamante, for data collection and management; Xuan Zhou and Madhusudhan Reddy Papasani, for statistical expertise; Christine McCrary Sisk, for medical writing and editorial assistance; and Joseph C Naggar and Michele McColgan, for administrative or logistical support. Breast Cancer Research Foundation, BCRF; Pfizer; AstraZeneca; Merck; Roche; Samsung; Merck Sharp and Dohme, MSD; Eisai

  • Publication . Article . 2010
    Open Access
    Authors: 
    Rosanna W. Peeling; Harvey Artsob; José L. Pelegrino; Philippe Buchy; Mary Jane Cardosa; Shamala Devi; Delia Enria; Jeremy Farrar; Duane J. Gubler; María G. Guzmán; +9 more

    Dengue is an arthropod-borne flavivirus that comprises four distinct serotypes (DEN-1, DEN-2, DEN-3 and DEN-4) that constitute an antigenic complex of the genus flavivirus, family Flaviviridae. Infection by one serotype induces life-long immunity against reinfection by the same serotype, but only transient and partial protection against infection with the other serotypes1,2. Dengue virus infections can result in a range of clinical manifestations from asymp tomatic infection to dengue fever (DF) and the severe disease dengue haemorrhagic fever/dengue shock syndrome (DHF/ DSS). Most dengue infections are asymptomatic or cause mild symptoms, which are characterized by undifferentiated fever with or without rash. Typical DF is characterized by high fever, severe headache, myalgia, arthralgia, retro-orbital pain and maculopapular rash. Some patients show petechiae, bruising or thrombocytopenia. The clinical presentation of acute dengue infection is non-specific but 5–10% of patients progress to severe DHF/DSS, which can result in death if it is not managed appropriately. Plasma extravasation is the main pathophysiological finding of DHF/ DSS, which differentiates it from DF. DHF/ DSS is characterized by high fever, bleeding, thrombocytopenia and haemoconcentration (an increase in the concentration of blood cells as a result of fluid loss). Approximately 3–4 days after the onset of fever, patients can present with petechiae, rash, epistaxis, and gingival and gastrointestinal bleeding. Pleural effusion and ascites are common. Some patients develop circulatory failure (DSS), presenting with a weak and fast pulse, narrowing of pulse pressure or hypotension, cold and moist skin and altered mental state. Although there are no specific antiviral treatments for dengue infection, patients usually recover when the need for fluid management is identified early and electrolytes are administered3. It has been proposed that the classification of dengue disease should be simplified as severe and non-severe dengue. This simplified classification would make patient management and surveillance easier4. There is a need for specific, inexpensive dengue diagnostic tests that can be used for clinical management, surveillance and outbreak investigations and would permit early intervention to treat patients and prevent or control epidemics. Progress is being made in primary prevention, with several candidate dengue vaccines in late phases of development as well as improved vector control measures. Additionally, new techniques for the early detection of severe disease such as the use of biomarkers have the potential to decrease morbidity and

  • Open Access English
    Authors: 
    Ondřej Kaplan; Jana Zarubova; Barbora Mikulová; Elena Filova; Jiřina Bártová; Lucie Bacakova; Eduard Brynda;
    Publisher: Public Library of Science (PLoS)

    We describe the production of a highly-active mutant VEGF variant, α2-PI1-8-VEGF121, which contains a substrate sequence for factor XIIIa at the aminoterminus designed for incorporation into a fibrin gel. The α2-PI1-8-VEGF121 gene was synthesized, cloned into a pET-32a(+) vector and expressed in Escherichia coli Origami B (DE3) host cells. To increase the protein folding and the solubility, the resulting thioredoxin-α2-PI1-8-VEGF121 fusion protein was co-expressed with recombinant molecular chaperones GroES/EL encoded by independent plasmid pGro7. The fusion protein was purified from the soluble fraction of cytoplasmic proteins using affinity chromatography. After cleavage of the thioredoxin fusion part with thrombin, the target protein was purified by a second round of affinity chromatography. The yield of purified α2-PI1-8-VEGF121 was 1.4 mg per liter of the cell culture. The α2-PI1-8-VEGF121 expressed in this work increased the proliferation of endothelial cells 3.9-8.7 times in comparison with commercially-available recombinant VEGF121. This very high mitogenic activity may be caused by co-expression of the growth factor with molecular chaperones not previously used in VEGF production. At the same time, α2-PI1-8-VEGF121 did not elicit considerable inflammatory activation of human endothelial HUVEC cells and human monocyte-like THP-1 cells.

  • Closed Access
    Authors: 
    Fatemeh Korminouri; Masoud Rahbari-Sisakht; Dipak Rana; Takeshi Matsuura; Ahmad Fauzi Ismail;
    Publisher: Elsevier BV

    Abstract Surface modified polyvinylidene fluoride (PVDF) hollow fiber membranes (HFMs) were spun via dry–wet spinning technique at different air–gap lengths (0–20 cm). The morphology of prepared membranes was evaluated by scanning electron microscopy (SEM) and atomic force microscopy (AFM). Membranes were also characterized in terms of gas permeation, overall porosity, collapsing pressure, critical water entry pressure (CEPw) and contact angle. To determine the CO 2 absorption flux of HFMs, a gas–liquid membrane contactor system was used. Experimental results of this study revealed that by increasing the air–gap distance from 0 to 20 cm, wetting resistance and contact angle of fabricated membranes increased due to enhancement of membrane surface hydrophobicity. The highest helium (He) permeation was achieved for the spun fiber at the air–gap of 10 cm. From CO 2 absorption experiment it was found that the hollow fiber spun at the air–gap of 10 cm had the maximum CO 2 absorption flux of 1.41 × 10 −3 mol/m 2 s at the absorbent flow rate of 300 ml/min, which was significantly higher than CO 2 absorption flux obtained by other researchers. It was also found that both highest He gas permeance and CO 2 absorption flux were controlled by the surface porosity of the hollow fiber due to the maximum values obtained. Thus, the choice of an appropriate air–gap distance for fabrication of surface modified membranes was found to be a promising method to improve CO 2 removal in membrane contactor systems.

  • Open Access
    Authors: 
    Maria Skaalum Petersen; Cecilie Bo Hansen; Marnar Fríðheim Kristiansen; Jógvan Páll Fjallsbak; Sólrun Larsen; Jóhanna Ljósá Hansen; Ida Jarlhelt; Laura Pérez-Alós; Bjarni á Steig; Debes Hammershaimb Christiansen; +6 more
    Publisher: Cold Spring Harbor Laboratory

    AbstractOnly a few studies have assessed the long-term duration of the humoral immune response against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).In this nationwide longitudinal study from the Faroe Islands with close to full participation of all individuals on the Islands with PCR confirmed COVID-19 during the two waves of infections in the spring and autumn 2020 (n=172 & n=233), samples were drawn at three longitudinal time points (3, 7 and 12 months and 1, 3 and 7 months after disease onset, respectively).Serum was analyzed with a direct quantitative IgG antibody binding ELISA to detect anti–SARS-CoV-2 spike RBD antibodies and a commercially available qualitative sandwich RBD ELISA kit measuring total antibody binding.The seropositive rate in the convalescent individuals was above 95 % at all sampling time points for both assays. There was an overall decline in IgG titers over time in both waves (p < 0.001). Pairwise comparison showed that IgG declined significantly from the first sample until approximately 7 months in both waves (p < 0.001). After that, the antibody level still declined significantly (p < 0.001), but decelerated with an altered slope remaining fairly stable from 7 months to 12 months after infection. Interestingly, the IgG titers followed a U-shaped curve with higher antibody levels among the oldest (67+) and the youngest (0– 17) age groups compared to intermediate groups (p < 0.001).Our results indicate that COVID-19 convalescent individuals are likely to be protected from reinfection up to 12 months after symptom onset and maybe even longer. We believe our results can add to the understanding of natural immunity and the expected durability of SARS-CoV-2 vaccine immune responses.

  • Open Access
    Authors: 
    Alexander K. C. Leung; Joseph M. Lam; Kin Fon Leong;
    Publisher: Bentham Science Publishers Ltd.

    Background: The diagnosis of solitary cutaneous mastocytoma is mainly clinical, based on lesion morphology, the presence of a positive Darier sign, and the absence of systemic involvement. Knowledge of this condition is important so that an accurate diagnosis can be made. Objective: To familiarize physicians with the clinical manifestations, diagnosis, evaluation, and management of a solitary cutaneous mastocytoma. Methods: A PubMed search was completed in Clinical Queries using the key term "solitary cutaneous mastocytoma". The search strategy included meta-analyses, randomized controlled trials, clinical trials, observational studies, and reviews. Only papers published in English language were included. The information retrieved from the above search was used in the compilation of the present article. Results: Typically, a solitary cutaneous mastocytoma presents as an indurated, erythematous, yellow- brown or reddish-brown macule, papule, plaque or nodule, usually measuring up to 5 cm in diameter. The lesion often has a peau d'orange appearance and a leathery or rubbery consistency. A solitary cutaneous mastocytoma may urticate spontaneously or when stroked or rubbed (Darier sign). Organomegaly and lymphadenopathy are characteristically absent. The majority of patients with skin lesions that erupt within the first two years of life have spontaneous resolution of the lesions before puberty. Treatment is mainly symptomatic. Reassurance and avoidance of triggering factors suffice in most cases. Conclusion: The diagnosis is mainly clinical, based on the morphology of the lesion, the presence of a positive Darier sign, and the absence of systemic involvement. A skin biopsy is usually not necessary unless the diagnosis is in doubt.

  • Open Access English
    Authors: 
    Ghasan Fahim Huseien; Mohammad Ismail; Nur Hafizah A. Khalid; Mohd Warid Hussin; Jahangir Mirza;
    Publisher: Elsevier

    This paper presents the solution molarity dependent microstructures and mechanical properties of multi-blend geopolymer mortars (GPMs). Geopolymer mortars were cured at ambient temperature under varying concentration (from 2 to 16 M) of sodium hydroxide (NH) solution. GPMs are by conducting mechanical tests such as compressive, split tensile and flexural strengths and characterised by microstructural studies, such as X-ray diffraction (XRD), scanning electron microscopy (SEM) and X-ray spectroscopy (EDS). The effect of Na2O, H2O content, solution modulus (SiO2:Na2O) and Na2O:Al2O3 on GPMs strength were determined. The flow ability and setting time of such GPMs found to decrease linearly with increasing alkali concentration. Conversely, the GPMs comprehensive, split tensile and flexural strengths and the density are enhanced with increasing alkali concentration. Samples activated with 12 M NH solution are most strongly affected by silica dissolution. Furthermore, the ratio of (Na2O:Al2O3) was demonstrated to influence the compressive strength significantly and the (Na2O:Al2O3 = 0.84) presented the optimum strength. Keywords: Geopolymer, Alkali solution molarity, Compressive strength, Microstructure