bluuebunny/crossref_metadata_2025 huggingface dataset:
Values and preferences of men for undergoing prostate-specific antigen screening for prostate cancer: a systematic review
Authors: Vernooij Robin W M , Lytvyn Lyubov , Pardo-Hernandez Hector , Albarqouni Loai , Canelo-Aybar Carlos , Campbell Karen , Agoritsas Thomas
Published: September 2018

Objectives

To investigate men’s values and preferences regarding prostate-specific antigen (PSA)-based screening for prostate cancer.

Design

Systematic review.

Data sources

We searched MEDLINE, EMBASE, PsycINFO and grey literature up to 2 September 2017.

Eligibility criteria

Primary studies of men’s values and preferences regarding the benefits and harms of PSA screening.

Data extraction and synthesis

Two independent reviewers extracted data and assessed risk of bias with a modified version of a risk of bias tool for values and preferences studies, the International Patient Decision Aid Standards instrument V.3 and the Cochrane Collaboration risk of bias tool.

Results

We identified 4172 unique citations, of which 11 studies proved eligible. Five studies investigated PSA screening using a direct choice study design, whereas six used decisions aids displaying patient-important outcomes. The direct choice studies used different methodologies and varied considerably in the reporting of outcomes. Two studies suggested that men were willing to forego screening with a small benefit in prostate cancer mortality if it would decrease the likelihood of unnecessary treatment or biopsies. In contrast, one study reported that men were willing to accept a substantial overdiagnosis to reduce their risk of prostate cancer mortality. Among the six studies involving decision aids, willingness to undergo screening varied substantially from 37% when displaying a hypothetical reduction in mortality of 10 per 1000 men, to 44% when displaying a reduction in mortality of 7 per 1000. We found no studies that specifically investigated whether values and preferences differed among men with family history, of African descent or with lower socioeconomic levels.

Conclusion

The variability of men’s values and preferences reflect that the decision to screen is highly preference sensitive. Our review highlights the need for shared decision making in men considering prostate cancer screening.

Trial registration number

CRD42018095585.
Gross negligence manslaughter and doctors: ethical concerns following the case of Dr Bawa-Garba
Authors: Samanta Ash , Samanta Jo
Published: September 2018

Dr Bawa-Garba, a senior paediatric trainee who had been involved in the care of a child who died shortly after admission to hospital, was convicted of gross negligence manslaughter and subsequently erased from the medical register. We argue that criminalisation of doctors in this way is fraught with ethical tensions at levels of individual blameworthiness, systemic failures, professionalism, patient safety and at the interface of the regulator and doctor. The current response to alleged manslaughter during clinical care is not fit for purpose because of its narrow focus on criminalisation and punishment of individual doctors. The justice system fails to take into account systemic issues in a sufficiently proper and informed way particularly in respect of human factors involved in decision-making. It is easier to convict individual doctors for gross negligence manslaughter than it is to effect legal accountability upon organisations. If educational reflections are used to apportion blame, then this could impact detrimentally on honesty and the duty of candour, with negative implications for patient safety. Regulatory processes should not be deployed without consideration of context. There is an urgent need for a fresh and open evaluation of professional and societal expectations from the regulator that should include positive action as well as those that are proportionately punitive. Justice and patient safety would be served better by more sophisticated contextualisation through an approach that balances accountability in healthcare with failures that can occur within complex systems, and by working to a radical shift towards a just culture.
Treatment of experimentally induced bovine respiratory disease in young calves with a single administration of a combination of florfenicol and meloxicam
Authors: Achard Damien , Caruso‐Vares Agathe , Collin Jean‐François , McKelvie Joanne , Reddick David , Ramage Cliff
Published: September 2018

This study was designed to evaluate the efficacy of a new florfenicol/meloxicam combination (FMC) in calves with bovine respiratory disease. A total of 90 young calves were challenged via intratracheal deposition of 108 colony‐forming units ofMannheimia haemolytica. Data for 84 calves demonstrating a rectal temperature (RT) above 39.5°C and a combined total clinical score (TCS) greater than or equal to 3 were included. Calves were then randomly allocated to one of the three study groups (FMC; florfenicol/flunixin combination (FFC); or saline) and promptly treated. RT and TCS of calves treated with an FMC or FFC were consistently lower than RT and TCS of calves belonging to the control group (P<0.001). Moreover, at the end of the study, a high clinical cure rate was observed in calves treated with FMC (100 per cent) or FFC (96.6 per cent) whereas cure was limited for calves receiving saline (29.6 per cent). Interestingly, calves treated with FMC were cured without relapse more rapidly compared with calves treated with FFC (HR=1.76, P<0.05) and with a lower percentage of clinical relapse due to fever (P=0.05). These results underline the high efficacy of the FMC and are in line with the pharmacokinetic properties of florfenicol and meloxicam.
Research on Bus Interior Sound Quality Based on Masking Effects
Authors: Yuan J. , Cao X. , Wang D. , Chen J. , Wang S.
Published: September 2018

Masking effect is a very common psychoacoustic phenomenon, which occurs when there is a suitable sound that masks the original sound. In this paper, we will discuss bus interior sound quality based on the masking effects and the appropriate masking sound selection to mask the original sounds inside a bus. We developed three subjective evaluation indexes which are noisiness, acceptability and anxiety. These were selected to reflect passengers’ feelings more accurately when they are subject to the masking sound. To analyze the bus interior sound quality with various masking sounds, the subjective–objective synthesis evaluation model was constructed using fuzzy mathematics. According to the study, the appropriate masking sound can mask the bus interior noise and optimize the bus interior sound quality.
Some infinite families of congruences for overpartitions
Authors: Zhang Wenlong , Shi Ji
Published: September 2018

Let [Formula: see text] denote the number of overpartitions of [Formula: see text]. Recently, several infinite families of congruences modulo 12, 27 and 40 for [Formula: see text] have been established. In this paper, we investigate systematically some other infinite families of congruences modulo 12, 24 and 40 for [Formula: see text].
The Economics of 1.5°C Climate Change
Authors: Dietz Simon , Bowen Alex , Doda Baran , Gambhir Ajay , Warren Rachel
Published: September 2018

The economic case for limiting warming to 1.5°C is unclear, due to manifold uncertainties. However, it cannot be ruled out that the 1.5°C target passes a cost-benefit test. Costs are almost certainly high: The median global carbon price in 1.5°C scenarios implemented by various energy models is more than US$100 per metric ton of CO2in 2020, for example. Benefits estimates range from much lower than this to much higher. Some of these uncertainties may reduce in the future, raising the question of how to hedge in the near term. Maintaining an option on limiting warming to 1.5°C means targeting it now. Setting off with higher emissions will make 1.5°C unattainable quickly without recourse to expensive large-scale carbon dioxide removal (CDR), or solar radiation management (SRM), which can be cheap but poses ambiguous risks society seems unwilling to take. Carbon pricing could reduce mitigation costs substantially compared with ramping up the current patchwork of regulatory instruments. Nonetheless, a mix of policies is justified and technology-specific approaches may be required. It is particularly important to step up mitigation finance to developing countries, where emissions abatement is relatively cheap.
A novel mutual information estimator to measure spike train correlations in a model thalamocortical network
Authors: Gribkova Ekaterina D. , Ibrahim Baher A. , Llano Daniel A.
Published: September 2018

The impact of thalamic state on information transmission to the cortex remains poorly understood. This limitation exists due to the rich dynamics displayed by thalamocortical networks and because of inadequate tools to characterize those dynamics. Here, we introduce a novel estimator of mutual information and use it to determine the impact of a computational model of thalamic state on information transmission. Using several criteria, this novel estimator, which uses an adaptive partition, is shown to be superior to other mutual information estimators with uniform partitions when used to analyze simulated spike train data with different mean spike rates, as well as electrophysiological data from simultaneously recorded neurons. When applied to a thalamocortical model, the estimator revealed that thalamocortical cell T-type calcium current conductance influences mutual information between the input and output from this network. In particular, a T-type calcium current conductance of ~40 nS appears to produce maximal mutual information between the input to this network (conceptualized as afferent input to the thalamocortical cell) and the output of the network at the level of a layer 4 cortical neuron. Furthermore, at particular combinations of inputs to thalamocortical and thalamic reticular nucleus cells, thalamic cell bursting correlated strongly with recovery of mutual information between thalamic afferents and layer 4 neurons. These studies suggest that the novel mutual information estimator has advantages over previous estimators and that thalamic reticular nucleus activity can enhance mutual information between thalamic afferents and thalamorecipient cells in the cortex.

NEW & NOTEWORTHY In this study, a novel mutual information estimator was developed to analyze information flow in a model thalamocortical network. Our findings suggest that this estimator is a suitable tool for signal transmission analysis, particularly in neural circuits with disparate firing rates, and that the thalamic reticular nucleus can potentiate ascending sensory signals, while thalamic recipient cells in the cortex can recover mutual information in ascending sensory signals that is lost due to thalamic bursting.
Digital Image Steganography Using LSB Substitution, PVD, and EMD
Authors: Pradhan Anita , Sekhar K. Raja , Swain Gandharba
Published: September 2018

To protect from pixel difference histogram (PDH) analysis and RS analysis, two hybrid image steganography techniques by appropriate combination of LSB substitution, pixel value differencing (PVD), and exploiting modification directions (EMD) have been proposed in this paper. The cover image is traversed in raster scan order and partitioned into blocks. The first technique operates on 2 × 2 pixel blocks and the second technique operates on 3 × 3 pixel blocks. For each block, the average pixel value difference, d, is calculated. If d value is greater than 15, the block is in an edge area, so a combination of LSB substitution and PVD is applied. If d value is less than or equal to 15, the block is in a smooth area, so a combination of LSB substitution and EMD is applied. Each of these two techniques exists in two variants (Type 1 and Type 2) with respect to two different range tables. The hiding capacities and PSNR of both the techniques are found to be improved. The results from experiments prove that PDH analysis and RS analysis cannot detect these proposed techniques.
Insight into the Mechanistic Basis of the Hysteretic-Like Kinetic Behavior of Thioredoxin-Glutathione Reductase (TGR)
Authors: Rendón Juan L. , Miranda-Leyva Mauricio , Guevara-Flores Alberto , Martínez-González José de Jesús , del Arenal Irene Patricia , Flores-Herrera Oscar , Pardo Juan P.
Published: September 2018

A kinetic study of thioredoxin-glutathione reductase (TGR) fromTaenia crassicepsmetacestode (cysticerci) was carried out. The results obtained from both initial velocity and product inhibition experiments suggest the enzyme follows a two-site ping-pong bi bi kinetic mechanism, in which both substrates and products are bound in rapid equilibrium fashion. The substrate GSSG exerts inhibition at moderate or high concentrations, which is concomitant with the observation of hysteretic-like progress curves. The effect of NADPH on the apparent hysteretic behavior of TGR was also studied. At low concentrations of NADPH in the presence of moderate concentrations of GSSG, atypical time progress curves were observed, consisting of an initial burst-like stage, followed by a lag whose amplitude and duration depended on the concentration of both NADPH and GSSG. Based on all the kinetic and structural evidence available on TGR, a mechanism-based model was developed. The model assumes a noncompetitive mode of inhibition by GSSG in which the disulfide behaves as an affinity label-like reagent through its binding and reduction at an alternative site, leading the enzyme into an inactive state. The critical points of the model are the persistence of residual GSSG reductase activity in the inhibited GSSG-enzyme complexes and the regeneration of the active form of the enzyme by GSH. Hence, the hysteretic-like progress curves of GSSG reduction by TGR are the result of a continuous competition between GSH and GSSG for driving the enzyme into active or inactive states, respectively. By using an arbitrary but consistent set of rate constants, the experimental full progress curves were successfully reproducedin silico.
Abruptio Placentae Caused by Hypertriglyceridemia-Induced Acute Pancreatitis during Pregnancy: Case Report and Literature Review
Authors: Yalcin Bahat Pınar , Turan Gokce , Aslan Cetin Berna
Published: September 2018

Background. Hormonal effects during pregnancy can compromise otherwise controlled lipid levels in women with hypertriglyceridemia and predispose to pancreatitis leading to increased morbidity for mother and fetus. Elevation of triglyceride levels is a risk factor for development of pancreatitis if it exceeds 1000 mg/dL. Pancreatitis should be considered in emergency cases of abdominal pain and uterine contractions in Emergency Department at any stage of pregnancy. We report a case of abruptio placentae caused by hypertriglyceridemia-induced acute pancreatitis. Also, literature review of cases of acute pancreatitis induced by hypertriglycaemia in pregnancy has been made. Case. A 22-year-old woman presented to our Emergency Department, at 35 weeks of gestation, for acute onset of abdominal pain and uterine contractions. Blood tests showed a high rate of triglyceride. The patient was diagnosed with abruptio placentae caused by hypertriglyceridemia-induced acute pancreatitis. Immediate cesarean section was performed and it was observed that blood sample revealed a milky turbid serum. Insulin, heparin, and supportive treatment were started. She was discharged on the 10th day. Conclusion. Consequently, patients with known hypertriglyceridemia or family history should be followed up more closely because any delay can cause disastrous conclusions for mother and fetus. Acute pancreatitis should be considered in pregnant women who have sudden onset, severe, persistent epigastric pain and who have a risk factor for acute pancreatitis.
The Perturbed Riemann Problem with Delta Shock for a Hyperbolic System
Authors: Han Xinli , Pan Lijun
Published: September 2018

In this paper, we study the perturbed Riemann problem with delta shock for a hyperbolic system. The problem is different from the previous perturbed Riemann problems which have no delta shock. The solutions to the problem are obtained constructively. From the solutions, we see that a delta shock in the corresponding Riemann solution may turn into a shock and a contact discontinuity under a perturbation of the Riemann initial data. This shows the instability and the internal mechanism of a delta shock. Furthermore, we find that the Riemann solution of the hyperbolic system is instable under this perturbation, which is also quite different from the previous perturbed Riemann problems.
Effect of Proparacaine 0.375%-Sodium Fluorescein 0.25% Eye Drop Mixture and Fluorescein Strip on Anterior Segment Parameters
Authors: Doğan Mustafa , Sabaner Mehmet Cem , Erol Mehmet Akif
Published: September 2018

Purpose. To determine the effect of proparacaine 0.375%-sodium fluorescein 0.25% eye drop mixture and fluorescein strip on anterior segment parameters commonly used in routine ophthalmology practice. Methods. 115 healthy volunteers without any systemic or ocular disease were divided into two groups. 57 volunteers were in the proparacaine 0.375%-sodium fluorescein 0.25% eye drop mixture group, and 58 volunteers were in the fluorescein strip group. Measurements (CCT (central corneal thickness), topographic pupil diameter, AD (aqueous depth), ACV (anterior chamber volume), ICA (iridocorneal angle), LLD (limbus-limbus distance), and CV (corneal volume)) were taken before and at 1, 5, 15, and 30 minutes after application. Results. 59 (51.3%) participants were female, and 56 (48.7%) were male. The mean age of the drop application group was 26.88 ± 8.03, and the mean age of the strip application group was 26.33 ± 7.28. The mean CCT was 556 ± 32 μm before drop application and 569 ± 30 μm in the 1st minute, 560 ± 32 μm in the 5th minute, and 559 ± 31 μm in the 15th minute. The change was statistically significant (p<0.001, p=0.005, and p=0.013, resp.). Before the strip application, mean CCT was 552 ± 36 μm, while it increased to 556 ± 36 μm at the 1st minute, and this change was statistically significant (p=0.002). The mean CV before dropping was 59.29 ± 3.53 mm3 and 60.62 ± 3.53 mm3 at the 1st minute and 59.66 ± 3.70 mm3 at the 5th minute, which was statistically significant (p<0.001 and p=0.034). Mean topographic pupil diameters at the 1st, 5th, 15th, and 30th minute after application of drops and strips were not significantly changed compared to the preapplication values in the AD, ACV, ICA, and LLD measurements. Conclusions. Proparacaine 0.375%-sodium fluorescein 0.25% eye drop mixture and fluorescein strip application lead to a temporary change in CCT and CV of the anterior segment parameters. Anterior segment measurements with the Scheimpflug camera have to be done before topical fluorescein application.
Demographic and Symptomatic Features of Voice Disorders and Their Potential Application in Classification Using Machine Learning Algorithms
Authors: Tsui Sheng-Yang , Tsao Yu , Lin Chii-Wann , Fang Shih-Hau , Lin Feng-Chuan , Wang Chi-Te
Published: September 2018

Background: Studies have used questionnaires of dysphonic symptoms to screen voice disorders. This study investigated whether the differential presentation of demographic and symptomatic features can be applied to computerized classification. Methods: We recruited 100 patients with glottic neoplasm, 508 with phonotraumatic lesions, and 153 with unilateral vocal palsy. Statistical analyses revealed significantly different distributions of demographic and symptomatic variables. Machine learning algorithms, including decision tree, linear discriminant analysis, K-nearest neighbors, support vector machine, and artificial neural network, were applied to classify voice disorders. Results: The results showed that demographic features were more effective for detecting neoplastic and phonotraumatic lesions, whereas symptoms were useful for detecting vocal palsy. When combining demographic and symptomatic variables, the artificial neural network achieved the highest accuracy of 83 ± 1.58%, whereas the accuracy achieved by other algorithms ranged from 74 to 82.6%. Decision tree analyses revealed that sex, age, smoking status, sudden onset of dysphonia, and 10-item voice handicap index scores were significant characteristics for classification. Conclusion: This study demonstrated a significant difference in demographic and symptomatic features between glottic neoplasm, phonotraumatic lesions, and vocal palsy. These features may facilitate automatic classification of voice disorders through machine learning algorithms.
Paradoxical skin reaction with infliximab treatment
Authors: Fernandes Larissa Starling de A. , Martinez Daniela , Lupi Omar , Lima Ricardo Barbosa , Martins Carlos José , D'`Acri Antonio
Published: September 2018

Considering the increased utilization of anti-TNF medications in the treatment of inflammatory and autoimmune diseases, dermatologists should be aware of the possible adverse skin reactions. We describe a case of inverted psoriasis due to the use of infliximab used in the treatment of inflammatory bowel disease.
Review of the genera Agelosus Sharp, 1889, Apostenolinus Bernhauer, 1934 and Apecholinus Bernhauer, 1933 (Coleoptera: Staphylinidae: Staphylinini: Staphylinina)
Authors: SMETANA ALEŠ
Published: September 2018

A taxonomic review of the genera Agelosus Sharp, 1889, Apostenolinus Bernhauer, 1934 and Apecholinus Bernhauer, 1933 is presented, including taxonomic history of the genera, their descriptions and keys to the species where applicable. Each species is described and illustrated, and all available bionomic and distributional data are presented. Agelosus caerulescens sp.n. (Yunnan), A. distigma sp.n. (China: Zhejiang), A. haeckeli sp.n. (Nepal), A. longicornis sp.n. (Japan: Shikoku), A. nigricollis sp.n. (China: Beijing Municipality, Hubei, Sichuan; North Korea), and A. schillhammeri sp.n. (China: Hubei) are described as new.Xanthocypus J. Müller, 1925 is removed from synonymy with Ocypus Leach, 1819 and moved as a resurrected synonym to Agelosus Sharp, 1889 (stat.res.)Ocypus fraternus Fairmaire, 1891, Agelosus ohkurai Hayashi, 1973, Ocypus aglaosemanticus He & Zhou, 2017, Ocypus liui He & Zhou, 2017 and Ocypus pterosemanticus He & Zhou, 2017 are transferred from Agelosus to Apecholinus Bernhauer, 1933 (comb.nov.), and Agelosus ohkurai and Agelosus pterosematicus are placed in synonymy with Apecholinus fraternus (syn.nov.).Staphylinus auroguttatus Cameron, 1932, Staphylinus bimaculatus Cameron, 1932 and Ocypus cameroni Smetana & Davies, 2000 (replacement name for bimaculatus Cameron, 1932) are transferred from Ocypus to Agelosus (comb.nov.) and placed in synonymy with Agelosus sikkimensis Bernhauer, 1920 (syn.nov.).Agelosus brevipennis Naomi, 1983, described as subspecies of Agelosus carinatus (Sharp, 1874), is placed in synonymy with Agelosus carinatus (syn.nov.).Agelosus chinensis J. Li, 1992 is transferred from Agelosus to Apecholinus Bernhauer, 1933 (comb.nov.) and placed in synonymy with Apecholinus fraternus (syn.nov.).Agelosus fushunicus J. Li, 2015 is placed in synonymy with Ocypus coreanus J. Müller, 1925 (syn.nov.).Agelosus unicolor masaoi Hyashi, 1991 is elevated to species rank (stat.nov,).Lectotype is designated for Ocypus weisei Harold, 1877.
New records of the family Dascillidae (Coleoptera) from China
Authors: JIN ZHENYU , QIN ZHAO , ŚLIPIŃSKI ADAM
Published: September 2018

New geographical records for 13 species of Dascillidae in China are provided, of which two, Dascillus vittatus (Pic, 1914) and D. russus Jin et al., 2013 are new Country records. In addition, we provide 10 new province records for 13 species of Chinese Dascillidae. The Yunnan Province holds the richest generic and species diversity of Dascillinae (3 genera, 20 species). A total of 32 species (74%) are Chinese endemics and Yunnan is also found to be the area with the highest endemicity (13 species).
Notes on the Stenus indubius group with descriptions of four new species from China (Coleoptera, Staphylinidae)
Authors: HU CHENG-ZHI , TANG LIANG
Published: September 2018

Four new species of the Stenus indubius group from China are described: S. yaoluopingus Hu & Tang, sp. n. from Anhui Province, S. lizipingus Hu & Tang, sp. n., and S. fuscus Hu & Tang, sp. n. from Sichuan Province, and S. absconditus Hu & Tang, sp. n. from Guizhou Province. The diagnostic characters of the new species are illustrated and a published key to Chinese species of the group by Puthz, 2017 is modified to include the new species. Additional records of some species of the group are also provided.
Taxonomy of Euschizomerus Chaudoir 1850 (Coleoptera: Carabidae: Panagaeinae) from India with a new species and new synonym
Authors: JITHMON V.A. , THOMAS SABU K.
Published: September 2018

Description of new species Euschizomerus devagiriensis sp. nov. from south India, synonymisation of Euschizomerus schuhi Kirschenhofer, 2000 with E. indicus Jedlicka, 1955, redescriptions and new records of the earlier reported Indian species with a key to the species are provided.
Metrocoris sikkimensis sp. nov. (Hemiptera: Heteroptera: Gerridae) from northeastern India, with a key to species of the compar group occurring in India
Authors: BASU SRIMOYEE , CHANDRA KAILASH , VENKATESAN THIRUVENGADAM
Published: September 2018

Metrocoris sikkimensis sp. nov. is described from Sikkim, northeastern India, compared with similar species, included in an identification key and its geographical distribution is mapped. This species is assigned to the Metrocoris compar group based on the venter of the body entirely blackish and the male fore femur slender and unarmed. It can be distinguished from other species of the group based on the dark mesosternum without yellow markings, by the apically curved male paramere without setae, and by the structure of male endosomal sclerites.
Inpatient Pediatric Epistaxis: Management and Resource Utilization
Authors: Ni Jonathan S. , Kohn Jocelyn , Levi Jessica R.
Published: September 2018

Objectives:

Epistaxis is a common condition that rarely warrants hospital admission in the pediatric population, making its inpatient management difficult to study. This study aims to use a nationwide database to analyze trends in the treatment of pediatric patients admitted with epistaxis and determine factors impacting total charges.

Methods:

The latest (2012) version of the Kids’ Inpatient Database (KID), Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality was used to identify weighted discharges with the primary diagnosis of epistaxis. Information regarding demographics, comorbidities, treatment, hospital burden, and other admission details were obtained. Linear regression was used to analyze factors suspected to increase cost.

Results:

Among 372 weighted discharges, the mean age was 9.68 years (SD = 5.79), and 60.0% were male. The most common comorbidities were thrombocytopenia, von Willebrand disease, and chronic sinusitis. The majority of admissions with epistaxis (56.7%) did not undergo any procedure to control epistaxis. Mean total charges was $30 208 (SD = $62 683) with a mean length of stay of 2.46 days (SD = 3.31). Independent predictors of increased charges included longer length of stay, admission from the emergency department, and median household income within the third quartile for patients’ ZIP codes. Midwest hospital region independently predicted decreased charges. Having a procedure to control epistaxis did not significantly impact cost.

Conclusions:

Pediatric epistaxis admissions often do not require long hospital stays or procedural control of the bleed. However, significant charges are incurred treating epistaxis. Awareness of factors impacting these charges can potentially improve resource utilization.
The Candrārkī of Dinakara: A Text Related to Solar and Lunar Tables
Authors: Kolachana Aditya , Montelle Clemency , Dhammaloka Jambugahapitiye , Melnad Keshav , Mahesh K , Vyas Pravesh , Ramasubramanian K , Sriram MS , Pai Venketeswara
Published: September 2018

A set of tables devoted to the sun and the moon, titled the Candrārkī (“Related to the moon and sun”), was compiled in Sanskrit by Indian astronomer Dinakara along with a short accompanying text, intended to give guidance on how to construct a calendar ( pañcāṅga) for any desired year and geographical circumstances. The epoch of this table-text is 9 April 1578. We present here an edition of the text, a literal translation, and detailed technical commentary.
Preparation and Characterization of Polyurethane Porous Membranes by Particulate-leaching Method
Authors: Iannace Salvatore , Di Maio Ernesto , Nicolais Luigi
Published: September 2018

Highly porous polyurethane foams were prepared by the particulate-leaching technique, using NaCl as water-soluble solid phase. Melt compounding and compression moulding were used to prepare polymer/salt composite samples. Foams with controlled porosity, surface/volume ratio and pore dimension distribution were therefore obtained after dissolution of salt in distilled water. Dissolution kinetic was evaluated and modelled as a function of filler composition and its size distribution. Kinetic increased by rising salt concentration and by reducing its average size.

Mechanical properties of the foams were correlated to their morphological structure and to the properties of polymeric component.
Influence of Cell Size on Re-Entrant Transformation of Negative Poisson's Ratio Reticulated Polyurethane Foams
Authors: Wang Yun-Che , Lakes Roderic , Butenhoff Amanda
Published: September 2018

Several foams of different cell-size, including Scott Industrial polyurethane foam with large cells (20 pores per inch, ppi, or 1.2 mm per pore, black), medium cells (65 ppi, or 0.4 mm per pore, green), and near-microcellular (100 ppi, 0.25 mm per pore, white), were processed over various time and temperature regimes to ascertain the role of cell size in transformation to negative Poisson's ratio materials. These foams were transformed successfully, and exhibited negative Poisson's ratio behavior. Poisson's ratio was measured using a new laser based setup. For all as-received (unprocessed) foams with different cell sizes, Poisson's ratio decreased with compressive axial strain and increased with tensile strain up to a maximum. The maximum Poisson's ratio in tension decreased as cell size increases. The strain at which maximum Poisson's ratio occurs, increased with cell size. In negative Poisson's ratio foams, minimum Poisson's ratios of −0.8, −0.5, and −0.4 for 20 ppi, 65 ppi, and 100 ppi foams, respectively were observed. Furthermore, the cell size effects on transformation parameters were also found.
Strategies for Achieving Microcellular LDPE Foams in Extrusion
Authors: Park Chul B. , Lee Patrick C. , Wang Jin , Padareva Valentina
Published: September 2018

This paper describes the fundamental process design for achieving microcellular foams using low-density polyethylene (LDPE) in extrusion. Microcellular foams are classified as foams with cell densities larger than 109cells/cm3and cell sizes in the order of 10 micrometers. Supercritical CO2was used as a blowing agent in microcellular foaming due to its high volatility, which greatly increases thermodynamic instability. Our previous studies have indicated that microcellular foams cannot be produced from pure LDPE in a conventional microcellular extrusion system because of the high activation energy for cell nucleation. To increase the cell-nuclei density, an attempt was made at reducing the free energy for bubble nucleation by heterogeneous cell-nucleation. LDPE blends, with a small amount of polystyrene (PS) and/or a nucleating agent, were employed to induce heterogeneous cell-nucleating spots. The amount of the PS phase was varied to determine the optimum content. Furthermore, the melt strength of LDPE was increased by crosslinking. Microcellular LDPE foams have been successfully obtained in extrusion and the materials and processing windows have been clearly identified. The amount of injected CO2was varied in order to investigate its effect on the cell-population density.
Study of Odours Coming Out of Polyurethane Flexible Foam Mattresses
Authors: Hillier K. , King D.A. , Henneuse C.
Published: September 2018

Quality of life in Western populations is becoming an ever-growing concern. Higher demands are made in regard to for example comfort and safety. Low emissions of volatile organic compounds and odour criteria have become key performance requirements in most applications. To address this issue, the entire supply chain, from producers to end-users attempts to find ways and means to identify, understand and reduce unexpected emissions and odours.

Standard test methods have been developed for the evaluation of a wide range of product/materials emissions. A wide variety of experimental techniques as well as instrumental methods have been used for the sampling and the identification/quantification of volatile components emitted by materials. Work reported here includes the sensory and chemical evaluation of volatiles at low concentration levels (usually in the ppm or even the ppb range).

This paper describes the work conducted by EUROPUR (European Association of Flexible Polyurethane Foam Block Manufacturers) for the identification of odour emanating from PU samples. The data shown in this work gives some evidence for the potential contribution of very minor compounds emitted by PU samples to the odour. GC-MS-olfactometry was used to determine which components of the complex mixture of VOCs were primarily responsible for the perceived odour.
Extrusion Foam Coating of Coaxial Cables using Butane as Physical Blowing Agent
Authors: Marvian M. Nazari , Behravesh A. H. , Mahmoodi M. , Golzar M.
Published: September 2018

This paper presents an experimental study on manufacture and characterization of an insulating foam coating in the coaxial cables where a physical blowing agent (butane) is used. Coaxial cables with foam insulator are widely used in communication industries. The insulating foam plays a key role in the attenuation properties of the coaxial cables. In this research work, an extrusion setup was prepared to produce foam insulated coaxial cable using butane as the physical foaming agent. The effect of die geometry (die gap and die outlet diameter) on foam morphology and loss-attenuation were investigated using a blend of LDPE (90%)-HDPE (10%) as the main material. The results show that an acceptable low loss-attenuation is achievable via using a polyethylene compound and adjusting processing parameters.
Ten Year Storage Studies on Flame Retarded Polyurethane Foam
Authors: King D. A. , Walker J. , Harman D. J.
Published: September 2018

Three UK manufacturers of flexible polyurethane foam collaborated in a study in which cushion sized samples made from different formulations were stored for a period of ten years. Samples were monitored at approximately 6 monthly intervals for retained flame retardant. Two chlorinated phosphate ester flame retardants were investigated - TCPP and TDCP. Neither of these was prone to migration losses during the study period and foam ignition resistance was maintained.
Fabrication of Fine-celled PP/Ground Tire Rubber Powder Composites Using Supercritical Carbon Dioxide
Authors: Zhang Zhen-Xiu , Li Lin , Xin Zhen Xiang , Kim Jin Kuk
Published: September 2018

PP/Ground Rubber Tire (GRT) powder microcellular blend foams were prepared by supercritical carbon dioxide. The effects of blend composition like the content of GRT and maleic anhydride-grafted polypropylene (PP-g-MA) on crystallinity, solubility, diffusivity, morphology and mechanical properties of PP/GRT microcellular composites were studied. The results showed that the PP/GRT composite foams with a unique bimodal (large and small) cellular structure, in which the large-cells embrace a GRT powder. Depending on the composition, generally, the higher content of GRT results in the smaller cell sizes, higher cell densities and relative densities, whereas the 20 wt% GRT composite shows the lowest relative density. The mechanical properties of the microcellular PP/GRT composite foams are directly related to the blend composition and the processing conditions. The PP-g-MA/GRT (50/50) produced microcellular foams with a very fine and uniform cell structure, lower relative densities and improved mechanical properties.
Mechanical Properties and Morphology of Multifunctional Polypropylene Foams
Authors: Antunes M. , Realinho V. , Ardanuy M. , Maspoch M.Ll. , Velasco J.I.
Published: September 2018

One of the actual trends in polymer foams consists in the development of new materials by combining density reduction through foaming with the incorporation of functional fillers. This would enable to obtain materials with improved specific properties and added functionalities. There is also a growing interest in the use of environmentally-friendly materials obtained from renewable sources, thus coming as a logical step to combine both in order to create novel biocomposite foams. This work presents an overview of our recent results regarding the preparation and structural and thermo-mechanical characterizations of rigid polypropylene-based composite foams, with the main goal of developing new lightweight materials with tailor-made properties (multifunctional foams). Several reinforcements have been considered, from renewable cellulose fibres to nanometric-sized reinforcements such as silicate-layered nanoclays and carbon nanofibres.
Frequency Dependence of Poisson's Ratio of Viscoelastic Elastomer Foam
Authors: Dong L. , Lakes R.S.
Published: September 2018

All polymer foams are viscoelastic; for foams used in earplugs, this response is essential to their function. Poisson's ratio was inferred from viscoelastic response of earplug foam in torsion and bending. Poisson's ratio increases with frequency as a result of stress induced air flow. Air within the pores contributes to the overall bulk modulus at high frequency, but not at low frequency at which it easily flows when the foam is deformed. Such behaviour is the opposite of that of solid polymers in which the shear modulus varies with frequency much more than the bulk modulus.
Synthesis and Characterization of Polyols from Refined Cooking Oil for Polyurethane Foam Formation
Authors: Sipaut C.S. , Murni S. , Saalah S. , Hoon T.C. , Ibrahim M.N. Mohamad , Rahman I.A. , Abdullah A.A.
Published: September 2018

In this study, synthesized polyols from refined cooking oil, one of the ingredients in producing polyurethane (PU) foam, were investigated. The effects of reaction time, pH and type of solvents used on the properties of the polyols were characterized by using gas chromatography mass spectrometry (GC-MS), Fourier transform infrared (FTIR) spectroscopy and gel permeation chromatography (GPC). Further studies were carried out by using the synthesized polyols in combination with other chemicals for PU foam formation. The characterizations of the PU foams were performed through chemical, morphological and thermal analyses. The results showed that the polyols were synthesized successfully from refined cooking oil by using epoxidation and the hydroxylation process. 50% of the unsaturated fatty acids in the refined cooking oil were converted to saturated fatty acids and hydroxyl compounds as the reaction time increased up to five hours. However, the chemical contents in the polyols did not show significant changes as the pH value increased from pH3 to pH7. Using different types of solvent in the process showed that the hydroxyl content of the polyols ranged between 57 to 69 mg KOH/ g, with [Formula: see text] in the range of 15325 to 19320 g mol-1. The results also revealed that not all the synthesized polyols were suitable for PU foam formation. It is recommended in this study that the minimum hydroxyl content and molecular weight of the synthesized polyol required for PU foam formation is 69 mg KOH/ g and 19320 g mol-1 respectively. The properties of PU foam are highly dependent on the polyol and the water (blowing agent) content.
Proposed Fire Screening Tests on Plastic Foams with a Cone Calorimeter in Hong Kong
Authors: Chow W.K. , Han S.S. , Ni X.M.
Published: September 2018

Many big building fires happened in the past involved burning furniture foam. In some places such as Hong Kong, foams treated with fire retardant additives are only required to test their ignitability under a small flame. It was proposed earlier that the behaviour of furniture foam in flashover fires should be assessed more extensively by a cone calorimeter under high radiative heat fluxes. In this paper, this screening approach is further studied using five samples, including three different pillow foams, one mattress foam and one expensive fire-safe sofa foam. Both thermal and smoke aspects were studied in a cone calorimeter under heat fluxes of 20 kWm-2, 30 kWm-2, 50 kWm-2 and 70 kWm-2.

It was observed that all the foam samples were burnt under heat fluxes above 30 kWm-2. Only one pillow foam sample was not ignited under a low incident heat flux of 20 kWm-2, but it morphed into a mixture of solid and liquid. Under heat fluxes above 30 kWm-2, the fire-safe foam burnt vigorously; the burning showed no differences from foam without fire retardant. The fire-safe foam even released more smoke and toxic gases with higher carbon monoxide concentration. From the above cone calorimeter test, foams commonly used in the market can only withstand small match fires to delay ignition time. Foam products should be protected by additional provisions, such as an external cover, to protect them against big fires.
Polyurethane Foams with Carbazole Ring
Authors: Lubczak Renata
Published: September 2018

The oligoetherols obtained from carbazole, glycidol and oxiranes or alkylene carbonates were suitable substrates to obtain polyurethane foams. The foams were characterized by measuring their apparent density, water uptake, linear dimension changes and heat conductance. It has been found that polyurethane foams have a more enhanced thermal resistance than polyurethane foams obtained from oligoetherols synthesized from melamine and cyanuric acid and alkylene carbonates.
Rigid Polyurethane Foams Modified with Ground Tire Rubber - Mechanical, Morphological and Thermal Studies
Authors: Piszczyk Lukasz , Hejna Aleksander , Formela Krzysztof , Danowska Magdalena , Strankowski Michał
Published: September 2018

Rigid polyurethane foams, prepared by a single step method, were modified with the two types of ground tire rubber particles, i.e. untreated and thermo-mechanically reclaimed using a co-rotating twin screw extruder. The foaming process as well as the structure and the physical, mechanical and thermal properties of the resulting foams were investigated. The presence of ground tire rubber decreased the rate of polymerization. The incorporation of ground tire rubber decreased the total crosslink density of the produced material, as confirmed by a decrease in glass transition temperature measured by dynamic mechanical analysis and differential scanning calorimetry. The temperatures associated with a 10% and 50% mass loss of foam, determined by thermogravimetric analysis, increased due to the addition of ground tire rubber particles.
Investigating the Mechanical Response of Soy-Based Polyurethane Foams with Glass Fibers under Compression at various Rates
Authors: Obaid N. , Kortschot M. , Sain M.
Published: September 2018

Polyurethane foams have very diverse mechanical properties making them suitable for a wide range of applications. Their dependence on petroleum-based constituents, however, has prompted research in the preparation and investigation of foams made from bio-based components, such as polyol derived from soybean oil. Short fiber reinforcement has been found to improve the compressive modulus and plateau stress of the foams. In this study, elastic glass fibers were used to reinforce viscoelastic polyurethane foams; the compressive behaviour of the resulting foam was observed at various strain rates. At all strain rates, the fibers reinforced the foams, improving the modulus and plateau stress when compared to the properties of neat foam. A coupling between the fiber content and strain rate-dependence was observed in the modulus and plateau stress of the foams. Lastly, despite the increase in strength and stiffness of the foams, addition of fibers did not reduce the energy absorption of the foams.
Low Density Non-crosslinked Closed/Open Cell Polypropylene Foams with High Mechanical Properties
Authors: Escudero J. , Lopez-Gil A. , Laguna-Gutierrez E. , Rodriguez-Perez M.A.
Published: September 2018

Low density polypropylene based foams with different cellular structures have been produced by the improved compression molding route using a high melt strength polypropylene as polymer matrix. In addition, different types of nanoparticles have been introduced in the formulation (multi-wall carbon nanotubes, organomodified nanoclays and natural nanoclays) to modify the structure and properties. The results have showed a clear correlation between the open cell content of the foams and the mechanical properties in compression. In the unfilled polypropylene high specific mechanical properties are only achievable with low values of open cell content. In comparison, for an equal value of the interconnectivity between cells, the samples containing nanoclays present much higher specific properties. This result is attributed to the reinforcement of these nanoparticles in the solid matrix, due to an improved exfoliation during the foaming process and the presence of a bimodal cellular structure. The produced foams have interesting properties with stiffness similar to those of commercial polymer foams used for the core of sandwich panels.
Enhancement of Carbon Nanofibers Dispersion on Epoxy Resin Foams Leading to Remarkable Electrical Conductivity Improvement
Authors: Pinto J. , Velasco D. , Sutil S.B. , Boucher M. , Rodriguez-Perez M.A.
Published: September 2018

A simple procedure to evaluate and improve the dispersion of carbon nanofibers is presented and validated, relating the observed dispersion of the nanofibers in an intermediate stage of the production process to the final macroscopic properties of the foams. Epoxy/carbon nanofiber foams with optimal nanofiber dispersion are produced taking advantage of this procedure using inexpensive industrial vapor grown carbon nanofibers. Furthermore, the main characteristics and the electrical resistivity of the foams with improved nanofibers dispersion have been determined and related to the presence of the carbon nanofibers, greatly enhancing the electrical conductivity of the epoxy/carbon nanofiber foams.
Effects of Poly(butyleneadipate-co-terephthalate) as a Macromolecular Nucleating Agent on the Crystallization and Foaming Behavior of Biodegradable Poly(lactic acid)
Authors: Liu Wei , Chen Peng , Wang Xiangdong , Wang Fuchun , Wu Yujiao
Published: September 2018

The effect of a bio-based macromolecule, poly(butylene adipate-co-terephthalate) (PBAT), on the crystallization and foaming behavior of poly(lactic acid) (PLA) was evaluated. The crystallization kinetics results show that the addition of PBAT improved the crystallization of PLA by increasing the overall crystallinity and enhancing the crystal morphology of PLA. The massive crystallization zones may have prevented the escape of foaming gases to the surrounding area; the expansion ratio of the PLA foams increased from 4.87 to 10.94. Thus, a novel macromolecular crystallization nucleating agent for PLA was developed; the effect of the crystallization of PLA on its foaming behavior was also investigated. A high expansion ratio and finer cellular structure of PLA foam were obtained by optimizing the PBAT content.