bluuebunny/crossref_metadata_2025 huggingface dataset:
Consumption Rate of Lichens by Constrictotermes cyphergaster (Isoptera): Effects of C, N, and P Contents and Ratios
Authors: Barbosa-Silva Ana M. , Vasconcellos Alexandre
Published: January 2019

Wood is the main dietary item for most termites; however, supplementation with certain nutrients may occur via the ingestion of other available food resources in the ecosystem. The objective of this study was to evaluate the consumption of lichens with different C, N, and P contents by Constrictotermes cyphergaster under laboratory conditions, and estimate the intake of this substrate by this species in a semi-arid area of Northeast Brazil. The foraging activities of fifteen field colonies were monitored over 15 days from 6:00 p.m. to 6:00 a.m., and the lichens that were consumed were identified. Blocks of lichen thallus (1.5 × 1.5 cm) of four lichen species were offered to the termites in the laboratory. The mean total consumption rate of lichen by C. cyphergaster was 0.032 mg lichen/g termite (fresh weight)/day. Dirinaria confluens was the lichen most consumed by termites (0.010 mg lichen/g of termite (fresh weight)/day), followed by Lecanora spp. and Haematomma persoonii at a mean consumption of 0.008 and 0.006 mg lichen/g termite (fresh weight)/day, respectively. Based on the size of the C. cyphergaster populations, the estimated lichen consumption rate was 105.12 g lichen/ha/year. Lichen consumption was significantly affected by the N content and the C:N and C:P ratios, with the N content being the factor that best explained the consumption by the termites. The results suggest that C. cyphergaster can use lichens as a supplemental source of nutrients, especially nutrients that are found in low concentrations in wood.
Not only a Problem of Fatigue and Sleepiness: Changes in Psychomotor Performance in Italian Nurses across 8-h Rapidly Rotating Shifts
Authors: Di Muzio Marco , Reda Flaminia , Diella Giulia , Di Simone Emanuele , Novelli Luana , D’Atri Aurora , Giannini Annamaria , De Gennaro Luigi
Published: January 2019

Although many studies have detailed the consequences of shift work in nurses concerning health, fatigue, sleepiness, or medical errors, no study has been carried out trying to disentangle the contribution of sleepiness and fatigue associated to shift work from the attentional performance. The aim of this pilot study is (A) to investigate the effects of an 8-h rapidly rotating shift on fatigue and sleepiness among staff nurses and (B) how these factors affect their psychomotor performance. Fourteen nurses were selected for a within-subject cross-sectional study according to this sequence of shifts: morning–afternoon–night, which were compared as function of tiredness, sleepiness, and performance at the Psychomotor Vigilance Task (PVT). Subsequently, a within-subject Analysis of Covariance (ANCOVA) evaluated if the observed differences between shifts persist when the contribution of sleepiness is controlled. Our results clearly indicate that night shifts are associated with significant greater sleepiness and tiredness, and worsened performance at the PVT. As hypothesized, ANCOVA showed that these differences disappear when the contribution of sleepiness is controlled. Results point to a lower psychomotor performance in night compared to day shifts that depends on sleepiness. Hence, interventions to minimize the consequences of the night shift should consider a reduction of sleepiness.
A Literature Review of Proton Beam Therapy for Prostate Cancer in Japan
Authors: Hoshina Rika Maglente , Matsuura Taeko , Umegaki Kikuo , Shimizu Shinichi
Published: January 2019

Aim: Patients of proton beam therapy (PBT) for prostate cancer had been continuously growing in number due to its promising characteristics of high dose distribution in the tumor target and a sharp distal fall-off. Considering the large number of proton beam facilities in Japan, the further increase of patients undergoing this treatment is due to the emendations by Japanese National Health Insurance (NHI) and the development of medical equipment and technology, it is necessary to know what kind of research and advancements has been done on proton therapy for prostate cancer in the country. For these reasons, this literature review was conducted. The aim of this review is to identify and discuss research studies of proton beam therapy for prostate cancer in Japan. These include observational, interventional, and secondary data analysis of published articles. Method: A literature review on published works related to proton beam therapy for prostate cancer in Japan was conducted using articles that were gathered in the PubMed database of June 2018. We went through abstracts and manuscripts written in English with the keywords ‘proton beam therapy’, ‘prostate cancer’, and ‘Japan’. Results: A total of 23 articles were included. Fourteen articles were observational studies, most of which focused on the adverse effects of Proton Beam Therapy (PBT). Seven articles were interventional studies related on treatment planning, equipment parts, as well as target positioning. Two were secondary data analysis. The included studies were published in 13 different journals by different institutions using various equipment. Conclusion: Despite the favorable results of proton beam therapy, future research should include more patients and longer follow-up schedules to clarify the definitive role of PBT, yet, up to recent retrospective studies, included in this paper, concluded that PBT can be a suitable treatment option for localized prostate cancer. In addition, interventional studies were conducted by several institutions to further embellish proton therapy.
History and Evolution of Yttrium-90 Radioembolization for Hepatocellular Carcinoma
Authors: Saini Aman , Wallace Alex , Alzubaidi Sadeer , Knuttinen M. Grace , Naidu Sailendra , Sheth Rahul , Albadawi Hassan , Oklu Rahmi
Published: January 2019

Hepatocellular carcinoma (HCC) is the most common form of primary liver cancer and affects millions worldwide. Due to the lack of effective systemic therapies for HCC, researchers have been investigating the use of locoregional tumor control with Yttrium-90 (Y90) radioembolization since the 1960s. Following the development of glass and resin Y90 microspheres in the early 1990s, Y90 radioembolization has been shown to be a safe and efficacious treatment for patients with HCC across Barcelona Clinic Liver Cancer (BCLC) stages. By demonstrating durable local control, good long term outcomes, and equivalent if not superior tumor responses and tolerability when compared to alternative therapies including transarterial chemoembolization (TACE) and sorafenib, Y90 radioembolization is being increasingly used in HCC treatment. More recently, investigations into variations in Y90 radioembolization technique including radiation segmentectomy and radiation lobectomy have further expanded its clinical utility. Here, we discuss the history and evolution of Y90 use in HCC. We outline key clinical trials that have established the safety and efficacy of Y90 radioembolization, and also summarize trials comparing its efficacy to existing HCC treatments. We conclude by reviewing the techniques of radiation segmentectomy and lobectomy, and by discussing dosimetry.
Imperforate Hymen: A Comprehensive Systematic Review
Authors: Lee Keum , Hong Ji , Jung Hyuk , Jeong Hyun , Moon Seo , Park Woo , Jeong Yoon , Song Seung , Suk Yongjune , Son Min , Lim Jae , Shin Jae
Published: January 2019

Imperforate hymen (IH) is an uncommon congenital anomaly of the female genital tract, with the hymen completely obstructing the vaginal opening. Despite the simple diagnosis and treatment of IH, missed or delayed diagnosis is often a clinical problem owing to its low incidence, nonspecific symptoms, or insufficient physical examination. The aim of this study is to identify the characteristics, clinical presentations, treatment modalities, and outcomes of imperforate hymen patients. In this study, a literature search of PubMed databases was performed for sources published up to 3 July 2018 for English-language studies with the term “imperforate hymen”. The literature review identified 251 citations and 155 articles (143 case reports, 12 case series) containing 253 patients who were finally included (two papers were not written in English). Among 236 postnatal patients, the mean age of the patients was 10.7 ± 4.7 years. Abdominal pain (54.2%), urinary retention (20.3%), abnormal menstruation (14.0%), dysuria (9.7%), increased urinary frequency (5.1%), severe presentation of renal failure (n = 5, 2.1%), and urinary tract infection (n = 1, 0.4%) were presented. Most patients diagnosed with the condition underwent surgical treatment (83.5%), most of whom were treated via a hymenotomy (35.2%) and hymenectomy (36.4%), and the use of prophylactic antibiotics were only used in 7 patients. There were no differences in outcomes between two surgical methods. In addition, 141 (59.7%) patients showed improvement and 5 deceased patients were not related to IH or the operation itself; Complications, such as vaginal adhesion, were only noted in 6.6% of patients. In addition, among 17 cases of newborns with a diagnosis of IH before birth, hymenectomy (n = 5, 29.4%) and hymenotomy (n = 9, 52.9%) were the main treatment modalities and showed improved prognosis in 52.9% of newborns. Because IH diagnosis is easy and postsurgical prognosis is good, clinicians should carefully examine every female patient at birth. IH should be considered regarding adolescent girls with abdominal pain, lower back pain, or urinary retention, and perform appropriate physical examinations of the genital introitus. In addition, accurate diagnosis as IH, not misdiagnosing as vaginal septum or agenesis, is important to prevent severe complications such as stricture and ascending infection.
qSOFA is a Poor Predictor of Short-Term Mortality in All Patients: A Systematic Review of 410,000 Patients
Authors: Lo Ronson S. L. , Leung Ling Yan , Brabrand Mikkel , Yeung Chun Yu , Chan Suet Yi , Lam Cherry C. Y. , Hung Kevin K. C. , Graham Colin A.
Published: January 2019

Background: To determine the validity of the Quick Sepsis-Related Organ Failure Assessment (qSOFA) in the prediction of outcome (in-hospital and 1-month mortality, intensive care unit (ICU) admission, and hospital and ICU length of stay) in adult patients with or without suspected infections where qSOFA was calculated and reported; Methods: Cochrane Central of Controlled trials, EMBASE, BIOSIS, OVID MEDLINE, OVID Nursing Database, and the Joanna Briggs Institute EBP Database were the main databases searched. All studies published until 12 April 2018 were considered. All studies except case series, case reports, and conference abstracts were considered. Studies that included patients with neutropenic fever exclusively were excluded. Results: The median AUROC for in-hospital mortality (27 studies with 380,920 patients) was 0.68 (a range of 0.55 to 0.82). A meta-analysis of 377,623 subjects showed a polled AUROC of 0.68 (0.65 to 0.71); however, it also confirmed high heterogeneity among studies (I2 = 98.8%, 95%CI 98.6 to 99.0). The median sensitivity and specificity for in-hospital mortality (24 studies with 118,051 patients) was 0.52 (range 0.16 to 0.98) and 0.81 (0.19 to 0.97), respectively. Median positive and negative predictive values were 0.2 (range 0.07 to 0.38) and 0.94 (0.85 to 0.99), respectively.
Effectiveness of Hypertonic Saline Nasal Irrigation for Alleviating Allergic Rhinitis in Children: A Systematic Review and Meta-Analysis
Authors: Li Chia-Ling , Lin Hsiao-Chuan , Lin Chien-Yu , Hsu Teh-Fu
Published: January 2019

We aimed to explore the efficacy of hypertonic saline nasal irritation (HSNI) for improving nasal symptoms and quality of life, and for decreasing oral antihistamine consumption in children with allergic rhinitis (AR). We conducted a systematic search of PubMed, Medline, Cumulative Index to Nursing and Allied Health Literature, EMBASE, Chinese Electronic Periodicals Service, and Cochrane Library of Controlled Trials databases for prospective randomized, controlled trials assessing HSNI effects in children with AR and published before December 2017. Two authors independently assessed each trial’s quality and extracted data for a meta-analysis. We included four trails comprising 351 patients. HSNI improved patients’ nasal symptom scores (mean difference 1.82 points after treatment; 95% confidence interval (CI), 0.35–3.30; I2 = 64%; p = 0.02) and a significantly lower rescue antihistamine use rate (risk ratio (RR), 0.68; 95% CI, 0.48–0.95; I2 = 28%; p = 0.02). Analyses comparing HSNI with isotonic saline nasal irrigation (ISNI) showed better nasal symptom scores (mean difference, 1.22 points; 95% CI, 1.01–1.44; I2 = 0%; p < 0.001) in patients in the HSNI group, although the antihistamine use (RR, 0.84; 95% CI, 0.64–1.10; I2 = 0%; p = 0.2) and adverse effect rates were similar between groups. Compared with ISNI, HSNI may be a reasonable adjunctive treatment for children with AR.
Sex Differences in the Relation between Waist Circumference within the Normal Range and Development of Reflux Esophagitis
Authors: Yang Hyo-Joon , Chang Yoosoo , Park Soo-Kyung , Jung Yoon Suk , Park Jung Ho , Park Dong Il , Ryu Seungho , Sohn Chong Il
Published: January 2019

We examined the association of abdominal obesity and waist circumference within normal range with the incidence of reflux esophagitis, separately in men and women. This cohort study involved 142,679 Korean adults without reflux esophagitis, who underwent upper endoscopy at baseline and during follow-up. Waist circumference was categorized into the following quartiles: <80, 80.1–85, 85.1–90, and ≥90.1 cm in men; and <69.3, 69.3–74, 74.1–79.5, and ≥79.6 cm in women. During the 551,877.8 person-years of follow-up, 29,509 participants developed reflux esophagitis. The association between waist circumference quartiles and risk of reflux esophagitis significantly differed with sex (p for interaction < 0.001). In men, multivariable-adjusted hazard ratios (HRs) (95% confidence intervals (CIs)) comparing waist circumference quartiles 2, 3, and 4 to the lowest quartile were 1.03 (0.99–1.07), 1.08 (1.04–1.12), and 1.15 (1.10–1.19), respectively. In women, HRs (95% CIs) comparing quartiles 1, 2, and 4 to the 3rd quartile were 1.10 (1.04–1.17), 1.03 (0.98–1.10), and 1.07 (1.01–1.13), respectively. In this large cohort with endoscopic follow-up, the risk of reflux esophagitis increased with increasing waist circumference even within the normal range in men, whereas the risk increased with low normal waist circumference or with abdominal obesity in women, indicating a U-shaped association.
Deduction of Novel Genes Potentially Involved in Keratinocytes of Type 2 Diabetes Using Next-Generation Sequencing and Bioinformatics Approaches
Authors: Lin En-Shyh , Chang Wei-An , Chen Yang-Yi , Wu Ling-Yu , Chen Yi-Jen , Kuo Po-Lin
Published: January 2019

Keratinocytes constitute the major cell type of epidermis, which participates in re-epithelialization during wound repair and the immune defense response to pathogens. The aim of the current study was to explore the differentially expressed genes and novel microRNA (miRNA) regulations that are potentially involved in diabetic keratinocytes through next-generation sequencing (NGS) and bioinformatics approaches. A total of 420 differentially expressed genes between normal and diabetic keratinocytes were identified, and systematic bioinformatics analyses indicated that these differentially expressed genes were functionally enriched in interferon-alpha signaling, viral defense response, and immune response. Additionally, the potential miR-340-3p-DTX3L interaction that has been systematically validated in miRNA prediction databases was proposed to participate in the disrupted skin homeostasis, altering the defense and immune response of diabetic skin. The findings may provide new insights into understanding the pathogenesis of epidermal pathologies in diabetic patients and targeting novel molecules to advance diabetic skin care in clinical practice.
Candida sp. Infections in Patients with Diabetes Mellitus
Authors: Rodrigues Célia , Rodrigues Maria , Henriques Mariana
Published: January 2019

Candidiasis has increased substantially worldwide over recent decades and is a significant cause of morbidity and mortality, especially among critically ill patients. Diabetes mellitus (DM) is a metabolic disorder that predisposes individuals to fungal infections, including those related to Candida sp., due to a immunosuppressive effect on the patient. This review aims to discuss the latest studies regarding the occurrence of candidiasis on DM patients and the pathophysiology and etiology associated with these co-morbidities. A comprehensive review of the literature was undertaken. PubMed, Scopus, Elsevier’s ScienceDirect, and Springer’s SpringerLink databases were searched using well-defined search terms. Predefined inclusion and exclusion criteria were applied to classify relevant manuscripts. Results of the review show that DM patients have an increased susceptibility to Candida sp. infections which aggravates in the cases of uncontrolled hyperglycemia. The conclusion is that, for these patients, the hospitalization periods have increased and are commonly associated with the prolonged use of indwelling medical devices, which also increase the costs associated with disease management.
Perioperative Goal-Directed Therapy during Kidney Transplantation: An Impact Evaluation on the Major Postoperative Complications
Authors: Cavaleri Marco , Veroux Massimiliano , Palermo Filippo , Vasile Francesco , Mineri Mirko , Palumbo Joseph , Salemi Lorenzo , Astuto Marinella , Murabito Paolo
Published: January 2019

Background: Kidney transplantation is considered the first-choice therapy in end-stage renal disease (ESRD) patients. Despite recent improvements in terms of outcomes and graft survival in recipients, postoperative complications still concern the health-care providers involved in the management of those patients. Particularly challenging are cardiovascular complications. Perioperative goal-directed fluid-therapy (PGDT) and hemodynamic optimization are widely used in high-risk surgical patients and are associated with a significant reduction in postoperative complication rates and length of stay (LOS). The aim of this work is to compare the effects of perioperative goal-directed therapy (PGDT) with conventional fluid therapy (CFT) and to determine whether there are any differences in major postoperative complications rates and delayed graft function (DGF) outcomes. Methods: Prospective study with historical controls. Two groups, a PGDT and a CFT group, were used: The stroke volume (SV) optimization protocol was applied for the PGDT group throughout the procedure. Conventional fluid therapy with fluids titration at a central venous pressure (CVP) of 8–12 mmHg and mean arterial pressure (MAP) >80 mmHg was applied to the control group. Postoperative data collection including vital signs, weight, urinary output, serum creatinine, blood urea nitrogen, serum potassium, and assessment of volemic status and the signs and symptoms of major postoperative complications occurred at 24 h, 72 h, 7 days, and 30 days after transplantation. Results: Among the 66 patients enrolled (33 for each group) similar physical characteristics were proved. Good functional recovery was evident in 92% of the CFT group, 98% of the PGDT group, and 94% of total patients. The statistical analysis showed a difference in postoperative complications as follows: Significant reduction of cardiovascular complications and DGF episodes (p < 0.05), and surgical complications (p < 0.01). There were no significant differences in pulmonary or other complications. Conclusions: PGDT and SV optimization effectively influenced the rate of major postoperative complications, reducing the overall morbidity and thus the mortality in patients receiving kidney transplantation.
Biocompatible Polymer Nanoparticles for Drug Delivery Applications in Cancer and Neurodegenerative Disorder Therapies
Authors: Calzoni Eleonora , Cesaretti Alessio , Polchi Alice , Di Michele Alessandro , Tancini Brunella , Emiliani Carla
Published: January 2019

Polymer nanoparticles (NPs) represent one of the most innovative non-invasive approaches for drug delivery applications. NPs main objective is to convey the therapeutic molecule be they drugs, proteins, or nucleic acids directly into the target organ or tissue. Many polymers are used for the synthesis of NPs and among the currently most employed materials several biocompatible synthetic polymers, namely polylactic acid (PLA), poly lactic-co-glycolic acid (PLGA), and polyethylene glycol (PEG), can be cited. These molecules are made of simple monomers which are naturally present in the body and therefore easily excreted without being toxic. The present review addresses the different approaches that are most commonly adopted to synthetize biocompatible NPs to date, as well as the experimental strategies designed to load them with therapeutic agents. In fact, drugs may be internalized in the NPs or physically dispersed therein. In this paper the various types of biodegradable polymer NPs will be discussed with emphasis on their applications in drug delivery. Close attention will be devoted to the treatment of cancer, where both active and passive targeting is used to enhance efficacy and reduce systemic toxicity, and to diseases affecting the central nervous system, inasmuch as NPs can be modified to target specific cells or cross membrane barriers.
Prediction of the Leaf Primordia of Potato Tubers Using Sensor Fusion and Wavelength Selection
Authors: Rady Ahmed , Guyer Daniel , Kirk William , Donis-González Irwin R
Published: January 2019

The sprouting of potato tubers during storage is a significant problem that suppresses obtaining high quality seeds or fried products. In this study, the potential of fusing data obtained from visible (VIS)/near-infrared (NIR) spectroscopic and hyperspectral imaging systems was investigated, to improve the prediction of primordial leaf count as a significant sign for tubers sprouting. Electronic and lab measurements were conducted on whole tubers of Frito Lay 1879 (FL1879) and Russet Norkotah (R.Norkotah) potato cultivars. The interval partial least squares (IPLS) technique was adopted to extract the most effective wavelengths for both systems. Linear regression was utilized using partial least squares regression (PLSR), and the best calibration model was chosen using four-fold cross-validation. Then the prediction models were obtained using separate test data sets. Prediction results were enhanced compared with those obtained from individual systems’ models. The values of the correlation coefficient (the ratio between performance to deviation, or r(RPD)) were 0.95(3.01) and 0.9s6(3.55) for FL1879 and R.Norkotah, respectively, which represented a feasible improvement by 6.7%(35.6%) and 24.7%(136.7%) for FL1879 and R.Norkotah, respectively. The proposed study shows the possibility of building a rapid, noninvasive, and accurate system or device that requires minimal or no sample preparation to track the sprouting activity of stored potato tubers.
Semi-Automatic Algorithms for Estimation and Tracking of AP-Diameter of the IVC in Ultrasound Images
Authors: Karami Ebrahim , Shehata Mohamed S. , Smith Andrew
Published: January 2019

Acutely ill patients presenting with conditions such as sepsis, trauma, and congestive heart failure require judicious resuscitation in order to achieve and maintain optimal circulating blood volume. Increasingly, emergency and critical care physicians are using portable ultrasound to approximate the temporal changes of the anterior–posterior (AP)-diameter of the inferior vena cava (IVC) in order to guide fluid administration or removal. This paper proposes semi-automatic active ellipse and rectangle algorithms capable of improved and quantified measurement of the AP-diameter. The proposed algorithms are compared to manual measurement and a previously published active circle model. Results demonstrate that the rectangle model outperforms both active circle and ellipse irrespective of IVC shape and closely approximates tedious expert assessment.
New 1 km Resolution Datasets of Global and Regional Risks of Tree Cover Loss
Authors: Hewson Jennifer , Crema Stefano C. , González-Roglich Mariano , Tabor Karyn , Harvey Celia A.
Published: January 2019

Despite global recognition of the social, economic and ecological impacts of deforestation, the world is losing forests at an alarming rate. Global and regional efforts by policymakers and donors to reduce deforestation need science-driven information on where forest loss is happening, and where it may happen in the future. We used spatially-explicit globally-consistent variables and global historical tree cover and loss to analyze how global- and regional-scale variables contributed to historical tree cover loss and to model future risks of tree cover loss, based on a business-as-usual scenario. Our results show that (1) some biomes have higher risk of tree cover loss than others; (2) variables related to tree cover loss at the global scale differ from those at the regional scale; and (3) variables related to tree cover loss vary by continent. By mapping both tree cover loss risk and potential future tree cover loss, we aim to provide decision makers and donors with multiple outputs to improve targeting of forest conservation investments. By making the outputs readily accessible, we anticipate they will be used in other modeling analyses, conservation planning exercises, and prioritization activities aimed at conserving forests to meet national and global climate mitigation targets and biodiversity goals.
Real-World Synthetic Biology: Is It Founded on an Engineering Approach, and Should It Be?
Authors: Davies Jamie A.
Published: January 2019

Authors often assert that a key feature of 21st-century synthetic biology is its use of an ‘engineering approach’; design using predictive models, modular architecture, construction using well-characterized standard parts, and rigorous testing using standard metrics. This article examines whether this is, or even should be, the case. A brief survey of synthetic biology projects that have reached, or are near to, commercial application outside laboratories shows that they showed very few of these attributes. Instead, they featured much trial and error, and the use of specialized, custom components and assays. What is more, consideration of the special features of living systems suggest that a conventional engineering approach will often not be helpful. The article concludes that the engineering approach may be useful in some projects, but it should not be used to define or constrain synthetic biological endeavour, and that in fact the conventional engineering has more to gain by expanding and embracing more biological ways of working.
Dispersion of Nanoparticles in Lubricating Oil: A Critical Review
Authors: Chen Yan , Renner Peter , Liang Hong
Published: January 2019

Nanolubricants have attracted great interest due to the promise of friction and wear reduction by introducing nanoparticles. To date, the foremost challenge for developing a new nanolubricant is particle suspension. To understand the mechanisms of nanoparticle dispersion and identify bottlenecks, we conducted a comprehensive review of published literature and carried out an analysis of dispersion based on available data from the past 20 years. This research has led to three findings. First, there are two primary methods in dispersion: formulation with dispersant and surface modification. Second, surfactant and alkoxysilanes are primary chemical groups used for surface modification. Third, functionalization using surfactant is found to be suitable for nanoparticles smaller than 50 nm. For larger particles (>50 nm), alkoxysilanes are the best. The existence of a critical size has not been previously known. To better understand these three findings, we conducted an analysis using a numerical calculation based on colloidal theory. It revealed that a minimal thickness of the grafted layer in surfactant-modified nanoparticles was responsible for suspending small nanoparticles. For larger nanoparticles (>50 nm), they were suitable for silanization of alkoxysilane due to increased grafting density. This research provides new understanding and guidelines to disperse nanoparticle in a lubricating oil.
Weibull Statistical Analysis of Strength Fluctuation for Failure Prediction and Structural Durability of Friction Stir Welded Al–Cu Dissimilar Joints Correlated to Metallurgical Bonded Characteristics
Authors: Yang Chung-Wei , Jiang Shiau-Jiun
Published: January 2019

In this paper, dissimilar Al–Cu joints of AA1050H/C1100-Cu, AA6061-T6/C1100-Cu, and AA1050H/C2600-brass are successfully welded by a friction stir welding (FSW) process. The aim of the present study is not only to examine the tensile strength, but also to investigate the reliability, durability, and failure behaviors of joints as correlated with the metallurgical bonded microstructures of varied Al–Cu joints. Experimental evidence confirms that good welding quality for an FSW Al–Cu dissimilar joint is obtained when pure Cu and brass plates are positioned at the advancing side. Cross-sectional microstructures reveal that the AA6061-T6/C1100-Cu joint exhibits an extensive metallurgical bonded region with significant onion rings in the welding zone, whereas the AA1050H/C2600-brass joint generally displays a clear mechanical kissing bonded boundary at the joint interface. Al2Cu, Al4Cu9, and γ-Cu5Zn8 are major intermetallic compounds (IMCs) that are formed within the metallurgical bonded welding zone. The Weibull model provides a statistical method for assessing the failure mechanism of FSW Al–Cu joints. Better welding reliability and tensile properties with ductile dimpled ruptures are obtained for the Al–Cu joints with a typical metallurgical bonded zone. However, a mechanical kissing bonded interface and thick interfacial IMCs result in the deterioration of tensile strength with a brittle fracture and a rapid increase in the failure probability of Al–Cu joints.
A Novel PAN-GO-SiO2 Hybrid Membrane for Separating Oil and Water from Emulsified Mixture
Authors: Naseeb Noman , Mohammed Abdul Azeem , Laoui Tahar , Khan Zafarullah
Published: January 2019

In this article, we report the development of a polyacrylonitrile-graphene oxide-silicon dioxide (PAN-GO-SiO2) hybrid membrane for separation of oil and water from their emulsified mixture. The membrane was successfully fabricated using a one-step electrospinning process. GO and SiO2 nanofillers were added in PAN in different concentrations to determine the optimized composition for the PAN-GO-SiO2 hybrid membrane. A scanning electron microscopy (SEM) examination showed that the nanofillers were uniformly embedded in the nanofibrous structure of the electrospun hybrid membrane. The GO was mainly embedded inside the PAN nanofibers, causing knots while SiO2 nanoparticles were found embedded on the nanofiber surface, resulting in the formation of micro-nano protrusions on the fiber surface. The formation of these hierarchical structures, together with enhanced hydrophilicity due to oxygen containing groups on both SiO2 and GO, resulted in a high rejection (>99%) of oil from oil-water emulsion. Membrane performance evaluation under gravity separation tests showed that the separation flux and phase rejection was enhanced with the incorporation of nanofillers. The inclusion of nanofillers also enhanced the mechanical properties of the membrane. The best flux and phase separation performance was obtained for an optimized concentration of 7.5 wt % SiO2 and 1.5 wt % GO in PAN. The flux of separated water was enhanced from 2600 L m−2 h−1 for pristine PAN to 3151 L m−2 h−1 for PAN-GO-SiO2. The hybrid membrane also showed good mechanical and chemical stability, and antifouling propensity.
Carbon Nanotubes Enhance the Radiation Resistance of bcc Iron Revealed by Atomistic Study
Authors: Liu Shuzhuang , Xie Lu , Peng Qing , Li Rui
Published: January 2019

With extra space, a carbon nanotube (CNT) could serve as an absorber of point defects, including helium interstitials, and outgas the accumulate helium via “nano-chimneys”. The radiation resistance of CNT/Fe has still not been fully understood. Herein, we investigated the influence of CNTs on low-energy helium irradiation resistance in CNT/Fe composites by molecular dynamic simulations. CNTs reduced the small and medium He clusters in the Fe matrix. When the incident energy of the He atoms was 300 eV, the He atoms aggregated at the outer surface of CNTs. CNTs postponed the formation of He bubbles. When the irradiation energy was higher than 600 eV, He atoms could penetrate the walls of CNTs and form clusters inside the single-walled CNTs or the space in double-walled CNTs—the latter presented better performance. The reduction of Frenkel pair point defects suggested the enhancement of radiation resistance by the presentation of CNTs. Our results might be useful for the material design of advanced steels for radiation resistance.
Sequestration of Pb(II) Ions from Aqueous Systems with Novel Green Bacterial Cellulose Graphene Oxide Composite
Authors: Mensah Alfred , Lv Pengfei , Narh Christopher , Huang Jieyu , Wang Di , Wei Qufu
Published: January 2019

In this study, a novel green adsorbent material prepared by the esterification of bacterial cellulose (BC) and graphene oxide (GO), richly containing hydroxyl, alkyl, and carboxylate groups was characterised by FTIR (Fourier Transform infrared spectroscopy), XRD (X-ray diffraction), SEM (Scanning electron microscopy) and TGA (Thermo-graphimetric analysis). The specific surface area (SSA) and pore size distribution (PSD) analysis of materials were also analysed. Batch experiments–adsorption studies confirmed the material to have a very high Pb2+ removal efficiency of over 90% at pH 6–8. Kinetic studies showed that the uptake of metal ions was rapid with equilibrium attained after 30 min and fitted well with the pseudo-second-order rate model (PSO). Isotherm results with a maximum adsorption capacity (Qmax) of 303.03 mg/g were well described by Langmuir’s model compared to Freundlich. Desorption and re-adsorption experiments realised that both adsorbent and adsorbates could be over 90–95% efficiently recovered and reused using 0.1 M HNO3 and 0.1 M HCl.
Development of Organosilicon-Based Superhydrophobic Coatings through Atmospheric Pressure Plasma Polymerization of HMDSO in Nitrogen Plasma
Authors: Asadollahi Siavash , Profili Jacopo , Farzaneh Masoud , Stafford Luc
Published: January 2019

Water-repellent surfaces, often referred to as superhydrophobic surfaces, have found numerous potential applications in several industries. However, the synthesis of stable superhydrophobic surfaces through economical and practical processes remains a challenge. In the present work, we report on the development of an organosilicon-based superhydrophobic coating using an atmospheric-pressure plasma jet with an emphasis on precursor fragmentation dynamics as a function of power and precursor flow rate. The plasma jet is initially modified with a quartz tube to limit the diffusion of oxygen from the ambient air into the discharge zone. Then, superhydrophobic coatings are developed on a pre-treated microporous aluminum-6061 substrate through plasma polymerization of HMDSO in the confined atmospheric pressure plasma jet operating in nitrogen plasma. All surfaces presented here are superhydrophobic with a static contact angle higher than 150° and contact angle hysteresis lower than 6°. It is shown that increasing the plasma power leads to a higher oxide content in the coating, which can be correlated to higher precursor fragmentation, thus reducing the hydrophobic behavior of the surface. Furthermore, increasing the precursor flow rate led to higher deposition and lower precursor fragmentation, leading to a more organic coating compared to other cases.
Influence of Fiber Distribution and Orientation in the Fracture Behavior of Polyolefin Fiber-Reinforced Concrete
Authors: Enfedaque Alejandro , Alberti Marcos G. , Gálvez Jaime C.
Published: January 2019

Polyolefin fiber-reinforced concrete (PFRC) has become an attractive alternative to steel for the reinforcement of concrete elements, mainly due to its chemical stability and the residual strengths that can be reached with lower weights. The use of polyolefin fibers can meet the requirements of standards, although the main constitutive relations are based on experience with steel fibers. Therefore, the structural contributions of the fibers should be assessed by inverse analysis. In this study, the fiber dosage was fixed at 6 kg/m3, and both self-compacting concrete and conventional concrete were used to compare the influence of the positioning of the fibers. An idealized homogeneous distribution of the fibers with such fibers crossing from side to side of the specimen was added to self-compacting concrete. The experimental results of three-point bending tests on notched specimens were reproduced by using the cohesive crack approach. Hence, constitutive relations were found. The significance of this research relies on the verification of the formulations found to build constitutive relations. Moreover, with these results, it is possible to establish a higher threshold for the performance of PFRC and the difficulties of limiting the first unloading branch typical of fracture tests of PFRC.
Deformation Behavior and Microstructural Evolution during Hot Stamping of TA15 Sheets: Experimentation and Modelling
Authors: Li Zhiqiang , Qu Haitao , Chen Fulong , Wang Yaoqi , Tan Zinong , Kopec Mateusz , Wang Kehuan , Zheng Kailun
Published: January 2019

Near- α titanium alloys have extensive applications in high temperature structural components of aircrafts. To manufacture complex-shaped titanium alloy panel parts with desired microstructure and good properties, an innovative low-cost hot stamping process for titanium alloy was studied in this paper. Firstly, a series of hot tensile tests and Scanning Electron Microscope (SEM) observations were performed to investigate hot deformation characteristics and identify typical microstructural evolutions. The optimal forming temperature range is determined to be from 750 °C to 900 °C for hot stamping of TA15. In addition, a unified mechanisms-based material model for TA15 titanium alloy based on the softening mechanisms of recrystallization and damage was established, which enables to precisely predict stress-strain behaviors and potentially to be implemented into Finite Element (FE) simulations for designing the reasonable processing window of structural parts for the aerospace industry.
Post-Cracking Capacity of Glass Beams Reinforced with Steel Fibers
Authors: Corradi Marco , Speranzini Emanuela
Published: January 2019

A study concerning the flexural behavior of glass beams reinforced with steel fibers is presented in this paper. Two types of steel fibers were used for reinforcement, made of high strength and stainless steel. The coupling effect of the two materials was studied in terms of energy dissipation and failure loads, by comparing the elastic limits and the post-elastic behaviors of the reinforced glass beams. Results demonstrated that it is possible to increase the overall structural safety of a steel fiber reinforced glass beam. The relationship between the bending force and deflections was initially linear, however, following the opening of first cracks in the glass, the reinforcement steel material was able to withstand the tensile stresses, governing the overall post-elastic phase.
Neutrosophic Soft Expert Multiset and Their Application to Multiple Criteria Decision Making
Authors: Bakbak Derya , Uluçay Vakkas , Şahin Memet
Published: January 2019

In this paper, we have investigated neutrosophic soft expert multisets (NSEMs) in detail. The concept of NSEMs is introduced. Several operations have been defined for them and their important algebraic properties are studied. Finally, we define a NSEMs aggregation operator to construct an algorithm for a NSEM decision-making method that allows for a more efficient decision-making process.
PPF-Dependent Fixed Point Results for New Multi-Valued Generalized F-Contraction in the Razumikhin Class with an Application
Authors: Hammad Hasanen A. , De la Sen Manuel
Published: January 2019

In this paper, a new multi-valued generalized F-contraction mapping is given. Using it, the existence of PPF-dependent fixed point for such mappings in the Razumikhin class is obtained. Moreover, an application for nonlinear integral equations with delay is presented here to illustrate the usability of the obtained results.
Extending the Applicability of Two-Step Solvers for Solving Equations
Authors: Argyros Ioannis K. , Shakhno Stepan
Published: January 2019

We present a local convergence of two-step solvers for solving nonlinear operator equations under the generalized Lipschitz conditions for the first- and second-order derivatives and for the first order divided differences. In contrast to earlier works, we use our new idea of center average Lipschitz conditions, through which, we define a subset of the original domain that also contains the iterates. Then, the remaining average Lipschitz conditions are at least as tight as the corresponding ones in earlier works. This way, we obtain weaker sufficient convergence criteria, larger radius of convergence, tighter error estimates, and better information on the solution. These extensions require the same effort, since the new Lipschitz functions are special cases of the ones in earlier works. Finally, we give a numerical example that confirms the theoretical results, and compares favorably to the results from previous works.
A Study of an EOQ Model under Lock Fuzzy Environment
Authors: Maity Suman , De Sujit Kumar , Prasad Mondal Sankar
Published: January 2019

The present article was developed for the economic order quantity (EOQ) inventory model under daytime, non-random, uncertain demand. In any inventory management problem, several parameters are involved that are basically flexible in nature with the progress of time. This model can be split into three different sub-models, assuming the demand rate and the cost vector associated with the model are non-randomly uncertain (i.e., fuzzy), and these may include some of the retained learning experiences of the decision-maker (DM). However, the DM has the option of revising his/her decision through the application of the appropriate key vector of the fuzzy locks in their final state. The basic novelty of the present model is that it includes a computer-based decision-making process involving flowchart algorithms that are able to identify and update the key vectors automatically. The numerical study indicates that when all parameters are assumed to be fuzzy, the double keys of the fuzzy lock provide a more accurate optimum than other methods. Sensitivity analysis and graphical illustrations are made for better justification of the model.
The Neglected Marine Fungi, Sensu stricto, and Their Isolation for Natural Products’ Discovery
Authors: Overy David P. , Rämä Teppo , Oosterhuis Rylee , Walker Allison K. , Pang Ka-Lai
Published: January 2019

Despite the rapid development of molecular techniques relevant for natural product research, culture isolates remain the primary source from which natural products chemists discover and obtain new molecules from microbial sources. Techniques for obtaining and identifying microbial isolates (such as filamentous fungi) are thus of crucial importance for a successful natural products’ discovery program. This review is presented as a “best-practices guide” to the collection and isolation of marine fungi for natural products research. Many of these practices are proven techniques used by mycologists for the isolation of a broad diversity of fungi, while others, such as the construction of marine baiting stations and the collection and processing of sea foam using dilution to extinction plating techniques, are methodological adaptations for specialized use in marine/aquatic environments. To this day, marine fungi, Sensu stricto, remain one of the few underexplored resources of natural products. Cultivability is one of the main limitations hindering the discovery of natural products from marine fungi. Through encouraged collaboration with marine mycologists and the sharing of historically proven mycological practices for the isolation of marine fungi, our goal is to provide natural products chemists with the necessary tools to explore this resource in-depth and discover new and potentially novel natural products.
Illustrating and Enhancing the Biosynthesis of Astaxanthin and Docosahexaenoic Acid in Aurantiochytrium sp. SK4
Authors: Ye Jingrun , Liu Mengmeng , He Mingxia , Ye Ying , Huang Junchao
Published: January 2019

The marine thraustochytrids are a promising source of docosahexaenoic acid (DHA) and the ketocarotenoid astaxanthin. In this study, the biosynthetic pathways of these two important metabolites in Aurantiochytrium sp. SK4 was illustrated by the analyses of the genome, transcriptome, key enzymes, and pathway products. Two sets of genes were involved in two pathways for the biosynthesis of fatty acids. The absence of Δ-15 desaturase genes and the presence of docosapentaenoic acid (DPA), up to 12% of total fatty acids suggest that Aurantiochytrium sp. SK4 may synthesize DHA mainly via a polyketide synthase (PKS) pathway. Three enzymes, namely geranyl diphosphate synthase (GPPS), farnysyl diphosphate synthase (FPPS), and geranylgeranyle diphosphate synthase (GGPPS) were found to be involved in the formation of GGPP that was subsequently catalyzed to β-carotene by a trifunctional CrtIBY enzyme. β-Carotene might be ketolated and then hydroxylated into astaxanthin based on the carotenoid profiles. The formation of GGPP was proposed to be the limiting steps for carotenoid production. Overexpression of the Archaeoglobus GPS together with the Escherichia coli isopentenyl pyrophosphate isomerase, and Vitreoscilla hemoglobin resulted in not only 1.85- and 5.02-fold increases of total carotenoids and astaxanthin, but also 2.40- and 2.74-fold increases of total fatty acids and DHA. This study provides insights into the biosynthesis of carotenoids and fatty acids in Aurantiochytrium.
Acidic Gases Separation from Gas Mixtures on the Supported Ionic Liquid Membranes Providing the Facilitated and Solution-Diffusion Transport Mechanisms
Authors: Akhmetshina Alsu , Yanbikov Nail , Atlaskin Artem , Trubyanov Maxim , Mechergui Amal , Otvagina Ksenia , Razov Evgeny , Mochalova Alla , Vorotyntsev Ilya
Published: January 2019

Nowadays, the imidazolium-based ionic liquids containing acetate counter-ions are attracting much attention as both highly selective absorbents of the acidic gases and CO2 carriers in the supported ionic liquid membranes. In this regard, the investigation of the gas transport properties of such membranes may be appropriate for better understanding of various factors affecting the separation performance and the selection of the optimal operating conditions. In this work, we have tested CH4, CO2 and H2S permeability across the supported ionic liquid membranes impregnated by 1-butyl-3-methylimidazolium acetate (bmim[OAc]) with the following determination of the ideal selectivity in order to compare the facilitated transport membrane performance with the supported ionic liquid membrane (SILM) that provides solution-diffusion mechanism, namely, containing 1-butyl-3-methylimidazolium tetrafluoroborate (bmim[BF4]). Both SILMs have showed modest individual gases permeability and ideal selectivity of CO2/CH4 and H2S/CH4 separation that achieves values up to 15 and 32, respectively. The effect of the feed gas mixture composition on the permeability of acidic gases and permeselectivity of the gas pair was investigated. It turned out that the permeation behavior for the bmim[OAc]-based SILM toward the binary CO2/CH4, H2S/CH4 and ternary CO2/H2S/CH4 mixtures was featured with high acidic gases selectivity due to the relatively low methane penetration through the liquid phase saturated by acidic gases.