bluuebunny/crossref_metadata_2025 huggingface dataset:
Cervical Cancer Burden and Opportunities for Prevention in a Safety-Net Healthcare System
Authors: Pruitt Sandi L. , Werner Claudia L. , Borton Eric K. , Sanders Joanne M. , Balasubramanian Bijal A. , Barnes Arti , Betts Andrea C. , Skinner Celette Sugg , Tiro Jasmin A.
Published: September 2018

Background:

The high prevalence of cervical cancer at safety-net health systems requires careful analysis to best inform prevention and quality improvement efforts. We characterized cervical cancer burden and identified opportunities for prevention in a U.S. safety-net system.

Methods:

We reviewed tumor registry and electronic health record (EHR) data of women with invasive cervical cancer with ages 18+, diagnosed between 2010 and 2015, in a large, integrated urban safety-net. We developed an algorithm to: (i) classify whether women had been engaged in care (≥1 clinical encounter between 6 months and 5 years before cancer diagnosis); and (ii) identify missed opportunities (no screening, no follow-up, failure of a test to detect cancer, and treatment failure) and associated factors among engaged patients.

Results:

Of 419 women with cervical cancer, more than half (58%) were stage 2B or higher at diagnosis and 40% were uninsured. Most (69%) had no prior healthcare system contact; 47% were diagnosed elsewhere. Among 122 engaged in care prior to diagnosis, failure to screen was most common (63%), followed by lack of follow-up (21%), and failure of test to detect cancer (16%). Tumor stage, patient characteristics, and healthcare utilization differed across groups.

Conclusions:

Safety-net healthcare systems face a high cervical cancer burden, mainly from women with no prior contact with the system. To prevent or detect cancer early, community-based efforts should encourage uninsured women to use safety-nets for primary care and preventive services.

Impact:

Among engaged patients, strategies to increase screening and follow-up of abnormal screening tests could prevent over 80% of cervical cancer cases.
Hypernasal Speech Is Perceived as More Monotonous than Typical Speech
Authors: Tardif Monique , Berti Larissa Cristina , Marino Viviane Cristina de Castro , Pardo Jennifer , Bressmann Tim
Published: September 2018

Background/Purpose: Anecdotal clinical reports have stated that hypernasal speech sounds monotonous. However, the relationship between the perception of intonation (i.e., the fundamental frequency variation across an utterance) and hypernasality (excessive nasal resonance during the production of non-nasal sounds) has not been investigated in research. We hypothesized that auditory-perceptual ratings of intonation would be significantly lower for more hypernasal stimuli. Methods: One male and one female voice actor simulated 3 levels of intonation (monotone, normal, and exaggerated) at 4 different levels of hypernasality (normal, mild, moderate, and severe). Thirty participants listened to the simulations and rated the intonation on a visual analogue scale from 0 (monotone) to 100 (exaggerated). Results: A mixed-effects ANOVA revealed main effects of intonation (F2 = 236.46, p < 0.001), and hypernasality (F3 = 159.89, p < 0.001), as well as an interaction between the two (F6 = 28.35, p < 0.001). Post hoc analyses found that speech was rated as more monotonous as hypernasality increased. Summary/Implications: The presence of hypernasality in speech can lead listeners to perceive speech as more monotonous. Instrumental measures should be used to corroborate auditory-perceptual evaluations of speech features like intonation.
Cognitive Impairment Along the Course of Depression: Non-Pharmacological Treatment Options
Authors: Listunova Lena , Roth Corinna , Bartolovic Marina , Kienzle Johanna , Bach Claudia , Weisbrod Matthias , Roesch-Ely Daniela
Published: September 2018

Major Depressive Disorder (MDD) is one of the most common psychiatric disorders, with a large global impact on both the individual and the society. In this narrative review, we summarize neurocognitive deficits during acute and (partially) remitted states of depression. Furthermore, we outline the potential negative effect of cognitive impairment (CI) on functional recovery, and discuss the role of several variables in the development of CI for MDD patients. Though there is cumulating evidence regarding persistent CI in unipolar depression, research on treatment options specific for this patient group is still scarce. Hence the central aim of our review is to present non-pharmacological interventions, which are thought to reduce CI in affected MDD patients. We discuss cognitive remediation therapy (CRT), physical exercise, yoga, mindfulness-based therapy, and modern neuromodulation approaches like neurostimulation and neurofeedback training. In conclusion, we propose future directions for research on CI in depression. Looking further ahead, we suggest creative interventional designs that include a direct comparison of different non-pharmacological treatment approaches on neurocognition and functional outcome of MDD. Furthermore, additive and synergistic effects of CRT with other treatment approaches should be examined and compared to create multimodal and even personalized intervention programs.
Comparison of Pain Characteristics in Patients with Rheumatoid Arthritis and Systemic Sclerosis with Particular Reference to the Neuropathic Pain Component: Cross-Sectional Study
Authors: Cengiz Gizem , Erol Kemal , Gok Kevser , Ozgocmen Salih
Published: September 2018

Objective: The aim of the study was to compare characteristics of pain in terms of neuropathic pain (NeP) and to assess the association between the neuropathic component and quality of life (QoL) in patients with systemic sclerosis (SSc) and rheumatoid arthritis (RA). Subjects and Methods: Fifty-four patients (47 females, 7 males) with SSc and 53 patients (46 females, 7 males) with RA were assessed for outcome measures including disease activity, physical functions, mental condition and health-related QoL (HRQoL) measures (Short Form-36; Hospital Anxiety and Depression Scale), and pain. NeP was assessed by the Douleur Neuropathique 4 (DN4) and PainDetect questionnaires in this cross-sectional study. Results: The patients had similar education, smoking status, functioning, and HRQoL. However, the patients with RA declared a more severe visual analogue scale of pain and a higher BMI than those with SSc. The NeP component was detected in 42.6% (n = 23) of the SSc patients and in 45.3% (n = 24) of the RA patients (p > 0.05) according to DN4. On PainDetect, possible NeP was detected in 13.0% (n = 7) versus 15.1% (n = 8), whereas 16.7% (n = 9) versus 17.0% (n = 9) were likely to have NeP in SSc and RA, respectively (p > 0.05). Most of the NeP characteristics were similar in SSc and RA, except for numbness and painful cold, which were notably more common in patients with SSc. Having the NeP component (according to DN4) had no influence on functioning and HRQoL in SSc; however, the NeP component revealed a heavier burden of disease regarding functional status, HRQoL, and psychometric components in RA. Conclusion: The NeP component was similar between patients with SSc and RA. However, NeP was associated with a heavier burden of disease in patients with RA.
CARRAGEENAN INDUCES CELL DEATH IN RATS BLOOD
Authors: Kopanytsia O. M. , Marushchak M. I. , Krynytska I. Ya.
Published: September 2018

Background. Because of its physical and chemical properties, carrageenan is fairly widely used. About 70 % of the carrageenan produced in the world is used in the food industry. Previous studies point to the development of oxidative stress in rats, by means of which carrageenan chronic enterocolitis was modeled.Objective. The aim of our study was to investigate the level of apoptosis and necrosis in the suspension of leukocytes in rats using 0.5 % and 1.0 % solutions of carrageenan.Methods. Annexin V (V) binding assays were performed using Annexin V Apoptosis Kit (Sigma Aldrich, USA), caspase rate in leukocyte-lymphocyte blood fractions was determined by spectrofotometry.Results. It was established that in the experimental application of carrageenan, the percentage of leukocytes with signs of apoptosis in both experimental groups statistically significantly increased. It was detected by the increased activity of effector caspase-3 in 1 month after the experiment in 1.5 times in the 2nd group and in 2.8 times in the 3rd group vs control data that point to caspase-dependent apoptotic pathway in case of carrageenan usage in rats.Conclusions. Oral use of carrageenan in rats was accompanied by the increase in the number of leukocytes with signs of apoptosis. The animals that consumed 1.0 % solution of carrageenan had more obvious increase in the activity of caspase-3 in serum relative to a group of rats consuming 0.5 % of carrageenan, proving the increase in the severity of apoptotic processes in intestine with the increase of the dose of carrageenan.
Measles - an old children's disease to remember
Authors: Custódio Marta , Strecht Tânia , Zelinová Jana , Marques Anabela
Published: September 2018

Measles is a serious, highly contagious viral disease. The measles virus is a single-stranded, RNA virus of the genus Morbillivirus within the family Paramyxoviridae, transmitted by air, through droplets of aerosols or by direct contact with respiratory secretions of infected individuals. The infection is acquired through the mucosa of respiratory tract or conjunctiva. In 2005, the World Health Organization established that measles eradication in the European Region should be achieved by 2010, but despite the measures adopted by the various countries, measles re-emerged, with 10271 cases reported only in 2013 in 30 states of European Union, with more than 91% of them in Germany, Italy, Netherland and United Kingdom. In the beginning of 2017, Portugal was threatened with a measles outbreak, reporting in the first five months of the year 31 confirmed cases, 20 (65%) of them in adults (18 or older), of which 45% (13) were in health professionals. Because this measles outbreak had so many cases in adults, the authors decided to make a brief review, trying to remember an old infection, not so well known by younger doctors, and that can be overlooked in the approach of the adult patients. The authors also point out that measles virus could virtually be eradicated as there is an effective vaccine and there is no reservoir in nature for the virus other than humans.
Molecular characterization and expression analysis of cathepsin C in the marine crab Charybdis japonica (A. Milne-Edwards, 1861) (Decapoda, Brachyura, Portunidae)
Authors: Chen Jian H. , Chen Hai G. , Gao Huan , Li Ying L. , Xu Xing H.
Published: September 2018

Cathepsin C is a crucial lysosomal cysteine proteinase that takes part in protein degradation and proenzyme activation. In this study, cDNA of cathepsin C in Charybdis japonica (A. Milne-Edwards, 1861) (designated as Cj-cath C) was cloned and characterized. The results showed that the open reading frame (ORF) of Cj-cath C was 1356 bp and encoded a protein of 451 amino acids. Cj-cath C contained two catalytic residues, a Cathepsin C exclusion domain and a Peptidase_C1 domain. The Cj-cath C was widely expressed in all tissues, with highest expression in hepatopancreas and heart. The transcript levels of Cj-cath C in the hepatopancreas and haemolymph were up-regulated after stimulation by Vibrio anguillarum Bergeman, 1909 and reached a peak value at 6 h post-infection, followed by a gradual decrease. These observations indicate that Cj-cath C might be a constitutive and inducible acute-phase protein that is involved in the immune defense of C. japonica.
Effects of specific wavelength spectra on antioxidant stress and cell damage of the ornamental cleaner shrimp Lysmata amboinensis (De Man, 1888) (Decapoda, Caridea, Lysmatidae) exposed to changing saline environments
Authors: Choe Jong Ryeol , Choi Ji Yong , Song Jin Ah , Choi Cheol Young
Published: September 2018

A variety of environmental factors have a major influence on the survival of aquatic organisms, particularly light and salinity, changes in which lead to a range of physiological changes. In the present study, we investigated the levels of stress caused by changes in salinity in the ornamental cleaner shrimp,Lysmata amboinensis, as well as the effect of specific light wavelengths following stress to changes in salinity. We measured the activity of superoxide dismutase (SOD), catalase (CAT), and lipid peroxidation (LPO) in the tissues (gill, hepatopancreas, and muscle) for three days after irradiating shrimp with specific wavelengths of light [red (630 nm), green (520 nm), and blue (455 nm)] at two intensities (0.5 and 1.0 W/m2) following exposure to different saline environments [25 practical salinity units (psu), 30 psu, 35 psu (normal seawater), and 40 psu]. DNA damage was measured using comet assays. Although all of the experimental groups exhibited negative results to changes in salinity, the green and red light groups exhibited positive effects when compared to the other wavelengths and fluorescent light. The effect of wavelength was not influenced by the intensity. In conclusion, the light of green and red wavelengths effectively reduces antioxidant stress and cell damage in cleaner shrimp.
Praying as a Form of Religious Coping in Dutch Highly Educated Muslim Women of Moroccan Descent
Authors: Pieper Joseph Z. T. , van Uden Marinus H. F. , van der Valk Leonie
Published: September 2018

This article addresses the research question: “How do Dutch highly educated Muslim women of Moroccan descent use prayer in dealing with problems?” The theoretical framework was mainly based on the work of Pargament et al. regarding religious coping. The empirical part of the study consisted of a quantitative and a qualitative part. This article presents results of the quantitative part. For the quantitative part of our research, 177 questionnaires were collected using snowball sampling. We asked respondents about their praying practices and their ways of religious coping, using the Brief RCOPE. The connection and communication in their prayer with a loving, caring, benevolent God is the main religious way in which these Muslim women of Moroccan descent cope with all kinds of problems. This use of prayer as a way of coping can be clarified through the psychological functions of religiosity and prayer that are suggested by Pargament, Koenig, and Perez (2000). Prayer could help them in: (1) finding meaning, (2) being master over their circumstances and controlling their emotions, (3) finding comfort and closeness to God, (4) experiencing intimacy with others and closeness to God, and (5) transforming their way of life. We did find few negative religious coping strategies, such as negative feelings towards God or alienation. This is in line with research results of Abu Raiya and Pargament (2010). As Islam implies surrender to God, it may be difficult for Muslims to admit their religious distress, doubts, and struggles.
Characterizing the Local and Intense Water Cycle during a Cold Air Outbreak in the Nordic Seas
Authors: Papritz Lukas , Sodemann Harald
Published: September 2018

Air masses in marine cold air outbreaks (CAOs) at high latitudes undergo a remarkable diabatic transformation because of the uptake of heat and moisture from the ocean surface, and the formation of precipitation. In this study, the fundamental characteristics of the water cycle during an intense and persistent, yet archetypal basinwide CAO from Fram Strait into the Nordic seas are analyzed with the aid of the tracer-enabled mesoscale limited-area numerical weather prediction model COSMO. A water budget of the CAO water cycle is performed based on tagged water tracers that follow moisture picked up by the CAO at various stages of its evolution. The atmospheric dynamical factors and boundary conditions that shape this budget are thereby analyzed. The water tracer analysis reveals a highly local water cycle associated with the CAO. Rapid turnover of water vapor results in an average residence time of precipitating waters of about one day. Approximately one-third of the total moisture taken up by the CAO falls as precipitation by convective overturning in the marine CAO boundary layer. Furthermore, precipitation efficiency increases as the CAO air mass matures and is exposed to warmer waters in the Norwegian Sea. These properties of the CAO water cycle are in strong contrast to situations dominated by long-range moisture transport that occur in the dynamically active regions of extratropical cyclones. It is proposed that CAOs in the confined Nordic seas provide a natural laboratory for studying local characteristics of the water cycle and evaluating its representation in models.
Associations Between Worksite Walkability, Greenness, and Physical Activity Around Work
Authors: Marquet Oriol , Floyd Myron F. , James Peter , Glanz Karen , Jennings Viniece , Jankowska Marta M. , Kerr Jacqueline , Hipp J. Aaron
Published: September 2018

This article explores the role of the work environment in determining physical activity gained within and around the workplace. With most adults spending more than half of their waking day at work, the workplace is a promising venue for promoting physical activity. We used a sample of 147 employed women—median age = 53 years old; 42% meeting Centers for Disease Control and Prevention (CDC) physical activity recommendations—wearing a GPS device and accelerometer on the hip for 7 days to assess location and physical activity at minute-level epochs. We analyzed the association between geographic information systems (GIS) measures of walkability and greenness around the workplace and the amount of physical activity gained while in the work neighborhood. Our results showed that working in high walkable environments was associated with higher levels of moderate to vigorous physical activity while at work, and with higher moderate to vigorous physical activity gained within the work neighborhood. Increasing walkability levels around workplaces can contribute to increasing physical activity of employees.
The Impact of an Automated Dispensing System for Supplying Narcotics in a Surgical Unit: The Experience of the National Cancer Institute Foundation of Milan
Authors: Portelli Giulia , Canobbio Michela , Bitonti Rossella , Della Costanza Chiara , Langella Roberto , Ladisa Vito
Published: September 2018

Objective: An automated dispensing system for narcotic drugs was introduced in a surgical unit to be compliant with the Italian narcotic drugs regulation. The aim of this study was to evaluate the impact of this automated dispensing system on the incidence of registry errors and corrections and on staff time and hospital costs. Methods: In 2014, Pyxis MedStation 3500 was introduced in a surgical unit of the National Cancer Institute of Milan, to improve the effectiveness of narcotics dispensing and avoid potential errors. Two different time periods of 8 months were compared, respectively, before and after the introduction of the automated dispensing system. In the pre-Pyxis period, drug movements were recorded through paper registries, while in the post-Pyxis period, electronic reports were automatically created from the system. For each period, the number of load/unload registry entries and corrections, the number of registry errors, the staff time dedicated to dispensing and registry activities, and stock and expired drug quantities were recorded. Results: Load and unload errors were reduced by 100% from the pre-Pyxis period to the post-Pyxis period, while registry corrections were lowered by 95%. Time dedicated from nurses to dispensing registration activities was reduced from 36 to 2 hours/month, while pharmacist time lowered from 9 to 1 hours/month. These time savings correspond to an economic saving of ~€4,120 and ~€3,730, respectively. In the post-Pyxis period, average operating room stock quantities were reduced versus the pre-Pyxis period, with wastage being 100% avoided. The reduction in stock drug quantities could correspond to an economic saving of ~€22,300 over the examined 8-month period, while the impact of drug wastage avoidance is modest (~€650). Conclusion: The overall economic impact of Pyxis use, over the 8-month time horizon in analysis, was around €31,000 saved or possibly converted into resource cost dedicated to other added value activities.
Community of common destiny: China’s “new assertiveness” and the changing Asian order
Authors: Smith Stephen N.
Published: September 2018

This essay will discuss China’s re-emergence as a great power through the lens of the English School. Following Ian Clark, I reconceptualize international society as a set of historically changing principles of legitimacy. I argue that China’s “new assertiveness” under Xi Jinping is best explained by China’s pursuit of legitimacy in an international arena where norms of legitimate modes of governance, development, and ordering principles have long been defined by the West. Furthermore, this essay will examine one recent development in Chinese International Relations theory, gongsheng, which purports to offer an alternative normative basis for interstate order, and probe its relationship to Xi Jinping’s recent declaration to build a “community of common destiny” in Asia.
Astrology With New Eyes: The Telescope in Astrological Prognostication
Authors: Ribeiro Luís Campos , Leitão Henrique
Published: September 2018

Telescope observations and celestial novelties of the early seventeenth century impacted not only in astronomy and science but in many other fields of culture, philosophy, and art. But what consequences did the telescope have to astrology, the body of knowledge with the closest ties to astronomy? Curiously, very little research has been made on this topic and current opinion seems to assume that astrology continued to be practised following much of the same premises it had for the previous centuries. In this paper, we present evidence that suggests otherwise: a common astrological judgement of a solar eclipse in 1652 (Lisbon, Biblioteca da Ajuda, Cod. 49-III-20, no. 15a) which includes prognostications made by interpreting the appearance of Venus when observed through a telescope shows that at least some astrologers were not unaffected by the telescope and this, in our opinion, opens a new line of research.
Traditional Femininity Versus Strong Black Women Ideologies and Stress Among Black Women
Authors: Davis Ashlee W. , Levant Ronald F. , Pryor Shana
Published: September 2018

The construct of femininity has typically been conceptualized from a Eurocentric perspective as traditional femininity ideology (TFI). This hegemonic femininity construction might not be fully applicable to African American women given their unique history and experiences. Moreover, the strong Black woman ideology (SBWI) which, although formulated during slavery, has become an adaptive and idealized cultural idealization. Both constructs have been associated with stress. The current study sought to investigate the relative strength of the links between TFI versus SBWI and perceived stress among a sample of African American women, and whether these relationships were moderated by feminine gender role stress and racial stress. Participants were 292 African American women recruited via social media and students from a Midwestern university for a web-based survey. As hypothesized, SBWI accounted for unique variance in perceived stress; however, TFI did not explain any of the variance. Results also indicated that gender role stress approached significance in its moderation of the link between TFI and perceived stress, although racial stress did significantly moderate the relationship between SBWI and perceived stress.
Six Years Later
Authors: Décary-Hétu David , Mousseau Vincent , Vidal Sabrina
Published: September 2018

Cryptomarkets are online illicit marketplaces where drug dealers advertise the sale of illicit drugs. Anonymizing technologies such as the Tor network and virtual currencies are used to hide cryptomarket participants’ identity and to limit the ability of law enforcement agencies to make arrests. In this paper, our aim is to describe how herbal cannabis dealers and buyers in the United States have adapted to the online sale of herbal cannabis through cryptomarkets. To achieve this goal, we evaluate the size and scope of the American herbal cannabis market on cryptomarkets and compare it to other drug markets from other countries, evaluate the impact of cryptomarkets on offline sales of herbal cannabis, and evaluate the ties between the now licit herbal cannabis markets in some States and cryptomarkets. Our results suggest that only a small fraction of herbal cannabis dealers and drug users have transitioned to cryptomarkets. This can be explained by the need for technical skills to buy and sell herbal cannabis online and by the need to have access to computers that are not accessible to all. The slow rate of adoption may also be explained by the higher price of herbal cannabis relative to street prices. If cryptomarkets were to be adopted by a larger portion of the herbal cannabis market actors, our results suggest that wholesale and regional distributors who are not active on cryptomarkets would be the most affected market’s participants.
Factors Influencing the Quality of Social Support Messages Produced Online: The Role of Responsibility for Distress and Others’ Support Attempts
Authors: Rains Stephen A. , Tsetsi Eric , Akers Chelsie , Pavlich Corey A. , Appelbaum Michael
Published: September 2018

Brunswik’s lens model was used as a guide to investigate the conditions under which people produce more and less effective support messages online. An experiment was conducted to examine the effects of identity cues concerning a support seeker’s responsibility for his or her distress and behavioral residue involving other online community members’ responses to the support seeker. Participants evaluated the support seeker more negatively, produced support messages containing lower levels of person-centeredness, and used fewer politeness strategies when the support seeker was more responsible for his or her distress than when the seeker was less responsible. These effects tended to be intensified when the quality of support from other community members was congruent with seeker responsibility compared with when others’ support and seeker responsibility were incongruent.
The need for not more, but more socially relevant audience participation in public service media
Authors: Vanhaeght Anne-Sofie
Published: September 2018

In public service media (PSM) theory and policy, it is argued that more audience participation is needed in the production of PSM programs. However, little research has been done on the actual implementation and evaluation of audience participation in practice. Therefore, we investigate the values and meanings media users attach to participatory opportunities in PSM. We focus on the case of Bel10, a radio project of the Flemish public broadcaster VRT, as audience participation in radio is an under-researched field. First, we look at the literature to provide an overview of the main challenges PSM is dealing with in relation to audience participation. Subsequently, we conduct 24 in-depth interviews with participants in the Bel10 project and 10 focus groups with non-participating listeners. Finally, we conclude that audience participation is especially valued by media users when it contributes to societal objectives, such as being critical of the status quo.
A Factorial Design Applied to the Extrusion Foaming of Polypropylene/Wood-Flour Composites
Authors: Matuana Laurent , Li Qingxiu
Published: September 2018

A factorial design was performed to determine the statistical effects of material compositions and extrusion processing variables on the foamability of polypropylene (PP)/wood-flour composites. Two levels with centrepoint values of wood flour content, chemical foaming agent (CFA) content, extruder's die temperature and screw speed were employed. The isolated main and interaction effects of these variables on the void fraction of foamed composite samples were analysed using Design Expert software. Statistical analysis of data revealed that the void fraction data was best fit with a linear model. The extruder's screw speed showed no discernible effect within the narrow range studied (20 to 50 rpm) whereas the other three main factors showed significant effects (values of “Prob > F” less than 0.0001) on the void fraction. Wood flour content/CFA content and wood flour content/die temperature constitute the important interaction effects. The experimental results indicate that void fraction of extrusion foamed composites is a strong function of the extruder's die temperature. A large amount of gas molecules available for the cell growth is not the only requirement for the production of composite foams with a high void fraction. Processing at a high die temperature is also very important for the development of proper viscoelastic properties of the matrix suitable for cell growth.
An Investigation into Claims that Toluene Diamine (TDA) is Present in Polyurethane Flexible Foams
Authors: Hillier K. , King D. , Kronborg-Hansen A. , Schupp T.
Published: September 2018

Claims have been made in Scandinavia that polyurethane flexible foams can be a health hazard because they contain, or on ageing can form, traces of the carcinogenic substance 2,4-toluene diamine (TDA). A working group was set up to investigate these claims and some of their findings are reported here. Analytical protocols have been refined for the determination of TDA extractable into aqueous based media. Extensive testing has been carried out on many different kinds of polyurethane foam without any evidence being found for the presence of free TDA. These negative results apply to both fresh cured foam and foam treated to simulate heat ageing, autoclaving and use in humid conditions. The reason for the erroneous reporting of TDA in foams undoubtedly lies in the use of the wrong pretreatment of the extract or the use of inappropriate sample injection techniques. This could range from not filtering the extract, increasing the pH of the extract prior to either gc/ms or lc/ms detection, or using hot on-column injection gc techniques. The false reporting of TDA is demonstrated here.
Viscoelastic Behaviour of Aluminium Silicate Filled Closed – Cell Microcellular Ethylene - Octene Copolymer Vulcanizates: Effect of Blowing Agent, Temperature, Frequency and Strain
Authors: Nayak N.C. , Tripathy D.K.
Published: September 2018

The dynamic viscoelastic behaviour of aluminium silicate filled closed-cell microcellular ethylene-octene copolymer vulcanizates has been studied at four frequencies of 3.5,11,35 and 110 Hz and at temperature varying from −100°C to + 100°C. A plot of log of storage modulus bears a linear relationship with the log of density for both solid and closed cell microcellular vulcanizates. The relative storage modulus decreases with decrease in relative density. It is also observed that both storage modulus and tan δ are temperature and frequency dependent. The storage modulus results are superposed to form master curves of the modulus vs. log temperature-reduced frequency, using shift factors calculated by the Arrhenius equation. Strain dependent isothermal dynamic mechanical analysis was performed for double strain amplitude (DSA) varying from 0.083% to 5%. The effects of blowing agent loading on storage modulus (E’) and loss tangent (tan δ) were also studied. Cole-Cole plots of microcellular vulcanizates show a circular arc relationship with density. Plots of tan δ against E’ were found to exhibit a linear relationship, the slope of which decreases with the increase in blowing agent loading. Empirical relationship between tan δ and E’ as well as Hysteresis and strain work have been found to be linear.
Rheological Behavior of Ethylene-Octene Copolymer Vulcanizates: Effect of Blowing Agent and Precipitated Aluminium Silicate Filler
Authors: Nayak N.C. , Bhattachariya A.K. , Tripathy D.K.
Published: September 2018

An experimental study of the rheological behaviour of aluminium silicate filled ethylene-octene copolymer vulcanizates in extrusion containing blowing agent has been carried out. The cell morphology development has been studied through scanning electron microscope. Rheological properties of unfilled and aluminium silicate filled systems with variation of blowing agent, extrusion temperature and shear rate have been studied using Monsanto processability tester (MPT). The total extrusion pressure (ΔPT), apparent shear stress (x), apparent viscosity (ηa), and die swell (%) of the unfilled and aluminium silicate filled compounds have been determined by using MPT. It is found that there is a reduction in stress and viscosity with blowing agent loading. It is observed that incorporation of blowing agent led to decreased shear thinning behaviour resulting in an increase in power law index. The viscosity reduction factor (VRF) of unfilled vulcanizates is found to be dependent on concentration of blowing agent, shear rate and temperature, whereas VRF of aluminium silicate filled vulcanizates is found to be independent of shear rate and temperature but dependent on blowing agent concentration.
Modeling Foam Growth in Semi-Crystalline Thermoplastics
Authors: den Doelder C.F.J. , Sammler R.L. , Koopmans R.J. , Paquet A.N.
Published: September 2018

The accurate description of the rapidly changing viscoelastic character of the gas-laden polymer melt during the expansion phase of foam development is one of the main challenges in modeling thermoplastic foam processing. A general model addressing this challenge for amorphous and semi-crystalline polymers is presented here. Key model elements include the capturing of strain hardening in extensional flow and flow-induced crystallization. The extensional rheology is modeled using the Lodge constitutive equation. The crystallization is modeled using the Avrami equation enhanced with a flow-induced Jay-factor. The model is applied to two isotactic polypropylene materials. The results show the complex non-linearity of foam expansion. The calculated foaming window is in good agreement with experimental data.
Modelling of Air Flow in Impacted Polyurethane Foam
Authors: Mills N.J. , Lyn G.
Published: September 2018

Polyurethane (PU) chip foam was characterised for air flow resistance, using a modification of the BS 4443 method, and for compressive impact response. A finite difference model was developed for the air flow in the impacted foam, including the effects of strain on foam permeability. It successfully predicted a non-uniform stress distribution across foam block of diameter > 100 mm, and showed that air flow is responsible for some but not all the hysteresis in this distribution for impact velocities > 3 m/s. Air pressure measurements, made in narrow vertical cavities inside impacted blocks of the foam, confirm the air pressure contribution to the total stress.
Morphology and Mechanical Properties of Foamed Polyethylene Blends
Authors: Zhang Yaolin , Rodrigue Denis , Aït-Kadi Abdellatif
Published: September 2018

Blends of polyethylene were foamed (593–782 kg/m3) by compression molding. Their morphology was investigated to understand the effect of polymer molecular structure. It was found that the cell diameter distribution can be approximated by a truncated normal distribution. Torsion, flexural and tensile properties were also measured at different strain rates. It was found that the shear, flexural and Young's moduli of blends and their foams increase with increasing strain rate, while their normalized moduli are almost unchanged. We also confirm that thin skins have a definite effect on shear and flexural moduli, but are negligible on tensile moduli. Finally, normalized yield strength and strain are almost independent on strain rate while break strain and toughness increase with increasing molecular weight and decreasing strain rate.
An Investigation into VOC Emissions from Polyurethane Flexible Foam Mattresses
Authors: Hillier K. , Schupp T. , Carney I.
Published: September 2018

Emissions of volatile species from flexible polyurethane foam mattresses were investigated by using large scale chamber tests designed to replicate the product use as mattress cores. Various trace impurities were identified and their concentrations were measured for input into a human health and toxicity risk assessment, which has concluded that none was injurious to health. The raw materials used to make the foam were analysed to identify the source of emanations and routes to their reduction or elimination. Several analytical artefacts were identified, and some recommendations made for their avoidance. Detailed product knowledge was essential to the reliable interpretation of analytical data. A quantitative risk assessment was carried out on each of the volatiles. No evidence of any human health risk was identified from the ‘worst-case’ exposure model employed
Foamability of Thermoplastic Vulcanizates (TPVs) with Carbon Dioxide and Nitrogen
Authors: Kim S.G. , Park C.B. , Kang B.S. , Sain M.
Published: September 2018

The foamability of thermoplastic vulcanizate (TPV) has been investigated in a customized foaming system using carbon dioxide (CO2) and nitrogen (N2) as a physical blowing agent. TPV or dynamic vulcanizate is a special class of thermoplastic elastomer that is produced by technological blending of a rubber and a thermoplastic simultaneously. The rubbery part was dynamically cured in a thermoplastic matrix. The influence of blowing agent content and the processing conditions on the expansion behaviour, the cell-number density and the foam structure are discussed. The TPV foam with N2produced a uniform and fine cell structure with a smooth surface, indicating that N2could be a very good physical blowing agent for TPV material.
Making Nano Technology Work in Foams using 1.5 Nanometer Titanate and Zirconate Coupling Agents - A Review
Authors: Monte Salvatore J.
Published: September 2018

A review of data and references are provided to demonstrate the efficacy of titanates and zirconates in foamed unfilled and filled polymers with an emphasis on their recent application in nanocomposites. Titanates (and zirconates) are shown to catalyze a polymer - called Repolymerization by the author - to increase its stress-strain strength thereby creating finer cells and reducing open cell structure because the polymer bubble does not break while being foamed. Additives such as foaming agents, fillers and reinforcements are shown to be dispersed better reducing interfacial failure. The chemistry of the Six Functions of the titanate molecule are discussed along with selection, dosage, the physics of mixing, catalysis and rheology, mixing temperatures, compounding considerations such as initial boiling point, and the chemistry at the interface of nano particulates.
Synthesis and Characterization of Porous Polyurethane-Chitosan Blends
Authors: Olivas-Armendariz Imelda , García-Casillas Perla E. , Martínez-Villafañe Alberto , Martinez-Pérez Carlos A.
Published: September 2018

In this work the synthesis and characterization of polyurethane (PU)-chitosan(CH) porous prepared by thermal induced phase separation (TIPS) is described, the obtained products were characterized by thermo gravimetric analysis (TGA) and differential scanning calorimetry (DSC), evidence of the interaction between both polymers was acquired from infrared spectroscopy. The morphology of the scaffolds was studied by scanning electron microscopy also the mechanical properties were acquired. The results showed that the TIPS technique is appropriate for the production of PU-CH porous materials.
Structural Characterization and Mechanical Behaviour of LDPE Structural Foams. A Comparison with Conventional Foams
Authors: Escudero J. , Solórzano E. , Rodriguez-Perez M.A. , Garcia-Moreno F. , De Saja J.A.
Published: September 2018

Structural foams are composed of two solid layers enclosing a foamed core. The application of sandwich structural foams has rapidly increased in the last decade. Injection moulding is currently used to produce these foams, being not common to produce conventional foams of similar densities and chemical compositions in a similar process. In this paper an alternative route to produce structural foams has been used. This method allows fabricating conventional foams with the same chemical composition and density than the structural foams, so comparisons between properties of both kinds of materials can be made in a proper way, i.e. avoiding effects of different chemical compositions and/or different densities. The structural and mechanical properties in tension, compression and bending have been characterized both for structural and conventional foams based on a low density polyethylene. The results have showed that the sandwich structure of structural foams improves a 50% the mechanical behaviour in bending, however no improvements in compression or tension have been found.
Analysis of the Expansion Behaviour of Rubber Compounds with Chemical Blowing Agents
Authors: Michaeli Walter , Sitz Sarah
Published: September 2018

Cellular elastomeric parts are used in various applications. Their cellular structure offers savings potential with respect to component weight, material consumption and costs. The foam structure is generated using chemical blowing agents, which are added to the rubber mixture before processing. Foaming and vulcanisation occur simultaneously in the curing unit. Both processes are adjusted by modification of the rubber mixture, which is one of the most challenging steps in rubber processing. The use of modified vulcameters for determination of the expansion of rubber mixtures is state of the art. However, this method is subject to several limitations. Therefore, IKV developed a new measurement system, which allows the analysis of the free expansion behaviour. Based on the Archimedean principle, the foaming process of rubber mixtures is recorded. A cell structure is generated, which can be analysed using digital image processing. In first experiments, several components of the rubber mixture are analysed using the measuring device in order to identify and categorise influencing parameters.
Investigation of the Corrugation in Foam Sheet Extrusion
Authors: Michaeli Walter , Hildebrand Tilo
Published: September 2018

Extruded foam sheets of low densities in combination with a homogenous distribution of fine-celled bubbles show a wavy pattern transverse to the machine direction. This effect known as corrugation is systematically investigated in a long-term research project at the IKV. The aim of the project is to determine the process and foam parameters which lead to corrugation and thereafter develop strategies to minimise the corrugation in foam extrusion. In this paper, the research project is presented and first results of the investigations are discussed.
A Comparison of the Effect of Different Flame Retardants on the Compressive Strength and Fire Behaviour of Rigid Polyurethane Foams
Authors: Barikani M. , Askari F. , Barmar M.
Published: September 2018

The influence of fire retardants on compressive strength and fire behaviour of rigid polyurethane foams was studied. The flame retardants studied included ammonium polyphosphate, melamine cyanurate, aluminum trihydrate, borax, and expanded graphite. The Limited Oxygen Index (LOI) showed that ammonium polyphosphate was consistently the most effective fire retardant at all filler levels tested. The one notable exception was expanded graphite, which produced an LOI of 22.7% at a relatively low 3.2% filler content. In general, the cell size decreased, and compressive strength increased, as filler % was increased. One exception to this trend was borax, which led to a significant loss in compression strength of PU when it was added at the 15% level.
Preparation of Molded Viscoelastic Polyurethane Foam for Pillow Applications
Authors: Rajan Krishna Prasad , Dhilipraj D. Bernard , Manikandan R. , Veena N.R.
Published: September 2018

There is a growing interest in developing and commercializing viscoelastic polyurethane foam suitable for pillow and mattress applications. In the present investigation, a novel combination of polyols with different molecular weights and hydroxyl values along with other ingredients were used for the preparation of viscoelastic polyurethane foam. The optimum polyol:isocyanate ratio was found to be 100:45 to yield a good quality foam. The physico-mechanical properties of the foam were measured as per standard procedures and compared with those of a commercially available viscoelastic foam sample. It was observed that the properties of the foam from this investigation were almost similar and in some aspects better than the properties of commercially available pillow foam. The foam can be further developed to make it suitable for hospital pillows and mattress applications.
Improving the Structure and Physical Properties of LDPE Foams using Silica Nanoparticles as an Additive
Authors: Saiz-Arroyo C. , Escudero J. , Rodríguez-Pérez M.A. , De Saja J.A.
Published: September 2018

Low density polyethylene/silica nanocomposites have been produced by melt blending and foamed in a high pressure autoclave by gas (CO2) dissolution. Different amounts of nanosilica, (from 1 wt% to 9 wt%) were used in order to analyze the influence of silica content on thermal and mechanical properties of both foamed and un-foamed composites.

It has been proved that the presence of silica nanoparticles modifies the structure and properties of both foamed and un-foamed materials. An increase in the crystallinity of the polymeric matrix as well as a decrease in cell size (for low contents of silica) have been observed. In addition it was found a significant increment of melt strength, thermal stability and mechanical properties for both solids and foams. From the obtained results, it has been concluded that silica particles play a multifunctional role in this system, and in addition to this, it has been demonstrated that the use of nanoparticles can produce synergetic effects, increasing foam mechanical properties in a greater extend than that of the solids.
Synergistic Effects of Modification with Nanoclay and Polystyrene on the Foaming Behavior of a Random Copolymerized Polypropylene
Authors: Wang Ming Yi , Ji Lian Qing , Chu Raymond , Park Chul B , Zhou Nan Qiao
Published: September 2018

Microcellular polypropylene/polystyrene/nanoclay (PP/PS/nanoclay) composites were processed in a continuous extrusion foaming system using supercritical CO2as the foaming agent. Neat PP foam showed quite a broad distribution of cell sizes and thick cell walls. Under the same foaming conditions, nanoclay and PS were introduced in the foaming process of PP. Consequently, foams with uniform cell size distribution, reduced cell size of 10~30 μm and enhanced cell-population density of 2.16×108cells/cm3were obtained. The heterogeneous nucleation of PS and nanoclay dramatically increased the nucleation rate, decreased the nucleation time interval, and hence facilitated an almost instantaneous growth of cell size. This method also provided new insight into the mechanism of improving the foaming performance of PP.
Development of Crystallization in PLA during Solid-State Foaming Process using Sub-Critical CO2
Authors: Wang Xiaoxi , Kumar Vipin , Li Wei
Published: September 2018

Crystallinity of PLA is an important factor that affects its processability, mechanical strength, biodegradability, and service temperature. In this paper crystallization of PLA in solid state foaming process was studied in two main aspects: gas sorption in saturation stage, and heating as well as stretching in foaming stage. During CO2 saturation the equilibrium crystallinity jumped from 9.7% at 2 MPa to 26.4% at 3 MPa CO2 pressure. Further increases in saturation pressure did not increase the crystallinity. In the gas sorption stage of the process, it was found that the crystallization reached equilibrium at approximately the same time as the gas sorption reached equilibrium. Within the range of 2 to 5 MPa saturation pressures and 60 to 100°C foaming temperatures, a maximum crystallinity of 26.8% was observed in the foamed PLA. Crystallinity increased with the extent of cell-wall stretching during the foaming process.