bluuebunny/crossref_metadata_2025 huggingface dataset:
Medical English M-Learning: Positioning a New Paradigm in E-Education
Authors: Arani Jafar Asgari
Published: January 2012

ABSTRACT- This study uses Depth Interview as a research instrument to study users' perceptions and acceptance of the potential use of mobile phones in a prospective design for learning Medical English, a mandatory course in medicine.

Almost all the respondents (93%) across graduates and students were unanimous about the need to learn English through M-Learning. When respondents were asked to suggest ideas on how medical English can be taught through mobiles (unaided question), 49% suggested SMS and 27% suggested SMS & Live Calls.

The survey indicates that there is a unanimous demand to learn English amongst students and graduates of medicine in a new e-education setting called M-learning. Constraints imposed by oneâ??s occupation and available resources expose the limitations of traditional learning and opens up a huge opportunity for M-English learning. Irrespective of differences, potential learners accepted the credibility of M-learning and displayed willingness to be an active user of an M-learning module. Diversity of responses on potential frequency of usage for SMSs, preferences regarding listening to IVR, speaking to Live Callers, traditional classroom learning, M-learning and testing options will establish at a primary level that the means of â??engagementâ??, â??presenceâ?? and â??flexibilityâ?? can be significantly different â??betweenâ?? and â??withinâ?? different educational groups.
Interaction of Ets-1 with HDAC1 Represses IL-10 Expression in Th1 Cells
Authors: Lee Choong-Gu , Kwon Ho-Keun , Sahoo Anupama , Hwang Won , So Jae-Seon , Hwang Ji-Sun , Chae Chang-Suk , Kim Gi-Cheon , Kim Jung-Eun , So Hong-Seob , Hwang Eun Sook , Grenningloh Roland , Ho I-Cheng , Im Sin-Hyeog
Published: January 2012

IL-10 is a multifunctional cytokine that plays a crucial role in immunity and tolerance. IL-10 is produced by diverse immune cell types, including B cells and subsets of T cells. Although Th1 produce IL-10, their expression levels are much lower than Th2 cells under conventional stimulation conditions. The potential role of E26 transformation-specific 1 (Ets-1) transcription factor as a negative regulator for Il10 gene expression in CD4+ T cells has been implicated previously. In this study, we investigated the underlying mechanism of Ets-1–mediated Il10 gene repression in Th1 cells. Compared with wild type Th1 cells, Ets-1 knockout Th1 cells expressed a significantly higher level of IL-10, which is comparable with that of wild type Th2 cells. Upregulation of IL-10 expression in Ets-1 knockout Th1 cells was accompanied by enhanced chromatin accessibility and increased recruitment of histone H3 acetylation at the Il10 regulatory regions. Reciprocally, Ets-1 deficiency significantly decreased histone deacetylase 1 (HDAC1) enrichment at the Il10 regulatory regions. Treatment with trichostatin A, an inhibitor of HDAC family, significantly increased Il10 gene expression by increasing histone H3 acetylation recruitment. We further demonstrated a physical interaction between Ets-1 and HDAC1. Coexpression of Ets-1 with HDAC1 synergistically repressed IL-10 transcription activity. In summary, our data suggest that an interaction of Ets-1 with HDAC1 represses the Il10 gene expression in Th1 cells.
Subarachnoid hemorrhage in Kashmir: Causes, risk factors, and outcome
Authors: Bhat Abdul , AfzalWani Mohammed , Kirmani Altaf
Published: January 2012

Context: Kashmir, a snow bound and mountain locked valley, is populated by about 7 million ethnic and non-migratory Kashmiris who have specific dietary and social habits than rest of the world. The neurological disorders are common in Kashmiri population. Aims: To study the prevalence and outcome of spontaneous intracranial subarachnoid hemorrhage (SAH) in Kashmir compared withother parts of the world. Settings and Design: A retrospective and hospital based study from 1982 to 2010 in the single and only Neurosurgical Centre of the State of Jammu and Kashmir. Materials and Methods: A hospital based study, in which, information concerning all Kashmiri patients was collected from the case sheets, patient files, discharge certificates, death certificates, and telephonic conversations with the help of Medical Records Department and Central Admission Register of Sher-i-Kashmir Institute of Medical Sciences, Kashmir India. Statistical Analysis: Analysis of variance and students T-test were used at occasions. Results: Incidence of SAH in Kashmiris is about 13/100,000 persons per year. SAH comprises 31.02% of total strokes and aneurysmal ruptures are cause of 54.35% SAHs. The female suffers 1.78 times more than the male. Total mortality of 36.60% was recorded against a good recovery of 14.99%. The familial SAHs and multiple aneurysms were also common. Intra-operative finding of larger aneurysmal size than recorded on pre-operative computed tomography (CT) angiogram of same patients was noteworthy. In 493 patients of SAH, the angiography revealed 705 aneurysms. Conclusion: Spontaneous intracranial subarachnoid hemorrhage, due to aneurysmal rupture, is common in Kashmir, with worst outcome. Food habits like "salt-tea twice a day", group-smoking of wet tobacco like "Jejeer", winter season, female gender, hypertension, and inhalation of"Kangri" smoke are special risk factorsof SAH, in Kashmiris. The plain CT brain and CT angiography are best diagnostic tools. The preventive measures for aneurysmal formation and rupture seems most promising management of future. The detachable endovascular aneurysmal occupying video assisted micro-camera capsules or plugs may be future treatment.
Pituitary hyperplasia resulting from primary hypothyroidism
Authors: Agrawal Amit , Diwan S
Published: January 2012

We report an unusual case of pituitary hyperplasia secondary to primary hypothyroidism clinically masquerading pituitary apoplexy. A 22-year-old female presented with intermittent headache, easy fatigability, facial puffiness, coarseness of facial features, and hoarseness of voice for six months duration. Diplopia and diminution of vision was also observed for the last 15 days. Brain imaging findings showed pituitary enlargement, the thyroid function test were suggestive of primary hypothyroidism. Patient did well with thyroid hormone replacement therapy.
Neuroleptic malignant syndrome and closed head injury: A case report and review
Authors: Shaikh Nissar , Al-Sulaiti Ghanem , Nasser Abdel , Rahman Muhammad
Published: January 2012

Neuroleptic malignant syndrome (NMS) is a rare, but potentially lethal neurological emergency. Fifty percent of traumatic brain injury (TBI) patients will have emotional disorders and post-traumatic agitations. Haloperidol is a neuroleptic antipsychotic medication commonly used in the traumatic brain injury patients due to its advantage of no effect on respiration and conscious level. But it is one of the common medications causing NMS. A 19-year-old male driver involved in the road traffic accident had an acute subdural hematoma, which was immediately evacuated. Postoperatively, he was awake. He was weaned from ventilator and extubated. He received 20 mg of intravenous haloperidol in divided doses with in 24 hours to control his agitation. Next day, he became drowsy, spastic, febrile, and tachycardic with labile blood pressure. He was diagnosed to have NMS, needed intubation, aggressive hydration and pharmacological treatment with dentrolene sodium and bromocriptin. He was weaned from ventilator and extubated on day 17. He was transferred to the ward and then discharged to be followed in out-patient clinic. NMS in head injury patient is rare and difficult to diagnose. Diagnosis of NMS should be suspected if two of the four cardinal signs and symptoms are developed following the use of neuroleptic or dopamine agonist medication withdrawal.
Spinal meningeal melanocytoma
Authors: Sen Rajeev , Sethi Divya , Goyal Vandana , Duhan Amrita , Modi Shilpi
Published: January 2012

Primary melanotic meningeal neoplasms are extremely rare lesions and benign forms are even rarer though with better prognosis than the malignant ones. We describe a 40-year-old male with a history of gradually progressive weakness of both lower limbs with normal bowel, bladder control, and an intradural mass measuring 1.5×1.0 cm on radiologic investigations. The lesion was surgically excised. Histopathologic examination revealed heavily melanin-pigmented cells, nuclei with reticulogranular chromatin and small nucleoli, moderate amount of eosinophillic cytoplasm with indistinct cell boundaries, and symplasmic appearance. A probable diagnosis of meningeal melanocytoma was made. The diagnosis was confirmed on immunohistochemical analysis which revealed strongly positive expression of HMB-45 in the tumor cells. Vimentin and S-100 were also diffusely positive while neuron specific enolase showed focal and patchy positivity; however, epithelial membrane antigen was distinctly negative.
Postlaryngectomy Tracheal Cast
Authors: Poddar Anil , Kedia Piyush
Published: January 2012

Tracheal cast formation postlaryngectomy is common in patients with dry, inspissated secretions, more so in dry weather, but is rarely large enough to cause significant respiratory distress. Our patient had significantly large tracheal casts to cause respiratory distress even with a widely patent tracheostoma.
A Case of Plummer-Vinson Syndrome Esophageal Web Dysphagia treated by Dilatation with Cuffed Endotracheal Tube
Authors: Naik Sudhir , Naik Sarika S , Ravishankara S , Shivakumar MC , Appaji Mohan K
Published: January 2012

Background/objectives

Plummer-Vinson syndrome also known as sideropenic dysphagia is a disease characterized by chronic iron-deficiency anemia, dysphagia and esophageal web. It commonly affects white female in the 4th to 7th decade. Most of the dysphagia and iron deficiency can be treated by iron supplementation and rarely web dilatation is needed.

Setting

Department of ENT, Head and Neck Surgery and Anesthesia, KVG Medical College, Sullia, Karnataka, India.

Case report

A 36-year-old female with dysphagia of 10 months and iron-deficiency anemia with a small upper esophageal web seen on upper GI endoscopy and barium swallow.

Intervention

Conservative line of management with blood transfusion and dilatation of the web with cuffed endotracheal tube.

Results

A good symptomatic and radiological improvement was seen after blood transfusion and web dilatation with cuffed endotracheal tube.

Conclusion

Cuffed endotracheal tube dilatation is a better way of managing upper esophageal webs with minimal complications under general anesthesia.
Intramuscular Hemangioma of the Masseter: Erectile Hemangioma
Authors: Jain Vikash , Bahri Nandini , Parekh Hiral P , Mody Swati S
Published: January 2012

Intramuscular hemangiomas are rare benign congenital neoplasms of vascular origin. They account for less than 1% of all hemangiomas and less than 20% of these are found in head and neck and present in 2nd and 3rd decade. The masseter is the most frequently involved site in the head and neck. Because of their infrequency, deep location and unfamiliar presentation, these lesions are seldom correctly diagnosed clinically and usually present as facial swelling causing facial asymmetry. A case of intramuscular hemangioma occurring in masseter muscle of an 8-year-old girl is presented here. Ultrasonography, color Doppler and Gd-enhanced MRI were performed and a presumptive diagnosis of hemangioma was considered which was subsequently confirmed by excision biopsy.
Prevalence of Dental Caries among 13 and 15-Year-Old School Children in an Endemic Fluorosis Area: A Cross-sectional Study
Authors: Sudhakar P , Reddy K Amarendher , Anuradha BR , Laxmi G Sri , Malik VN , Reddy S Nagalaxmi , Prasanna A Lakshmi
Published: January 2012

Aim

To assess the prevalence of dental caries and dental fluorosis among 13- to 15-year-old school children in Panyam, Andhra Pradesh, India.

Materials and methods

The cross-sectional study was conducted among 202 school children and were examined for dental fluorosis and dental caries.

Results

This study shows that male students have a decrease in DMFT (Decayed, missing, filled, teeth) index and increase in Dean's index when compared with females. Among students with 13 to 15 years of age, 13-year-old student has increase in DMFT score when compared with other age groups and 14-year-old students has increase in Dean's score when compared with other age group students.

Conclusion

The prevalence of dental caries decreased with the increase of fluorosis among the students examined.

Clinical significance

Patients with dental fluorosis show a decreased prevalence of dental caries.

How to cite this article

Anuradha BR, Sri Laxmi G, Sudhakar P, Malik VN, Reddy KA, Reddy SN, Prasanna AL. Prevalence of Dental Caries among 13 and 15-Year-Old School Children in an Endemic Fluorosis Area: A Cross-sectional Study. J Contemp Dent Pract 2011;12(6):447-450.
Scanning Electron Microscopic Study of Surface Epithelial Cells in Erosive and Nonerosive Oral Lichen Planus
Authors: Thakur Manjiri , Hazare Vinay
Published: January 2012

Aim

Aim of the study is to study the surface epithelial cells of erosive, nonerosive lichen planus by scanning electron microscope (SEM) and to correlate it with that of normal mucosa and oral leukoplakia.

Materials and methods

Twenty biopsies of lichen planus and five biopsies of normal mucosa were taken. Half piece of each biopsy was processed for H&E stain and another half for SEM study.

Result

Surface epithelial cells were showing different features.

Conclusion

Definite different features were seen in lichen planus-leukoplakia group than in normal oral mucosa. These changes are due to abnormality in cell maturation and differentiation.

Clinical significance

SEM study is helpful in early detection of dysplasia. It can lead to early treatment of the lesion and thus prevention of squamous cell carcinoma.

How to cite this article

Thakur M, Hazare V. Scanning Electron Microscopic Study of Surface Epithelial Cells in Erosive and Nonerosive Oral Lichen Planus. J Contemp Dent Pract 2011; 12(6):463-468.
Quorum Sensing in Plaque Biofilms: Challenges and Future Prospects
Authors: Biradar Baswaraj , Devi Prapulla
Published: January 2012

Aim

This review intends to provide a brief overview regarding quorum sensing among bacteria in biofilms and also attempts to throw light on the new research focusing on interference with the quorum sensing.

Background

Dental plaque is an example of microbial biofilm leading to periodontal disease and dental caries. Quorum sensing is widely employed by a variety of gram-positive and gram-negative bacterial species to coordinate various activities in biofilms. Quorum-sensing-interfering compounds have either a positive or a negative effect on the expression of bacterial phenotypes regulated by quorum sensing. These studies of bacterial quorum sensing have also suggested several ideal targets for drug design which can be promising in preventive and therapeutic aspects of periodontal diseases and dental caries.

Results

Studies have shown that periodontal disease and dental caries is caused by plaque biofilm bacteria. Quorum sensing is the means of communication between these bacteria to regulate a wide range of behavior patterns among them. The in vitro studies reviewed here have a vital role in opening up this field, because they reveal the basic machinery of cell—cell signaling in microbial communities. The signal machinery bacteria use to coordinate a variety of their activities is identified by these studies.

Further, this review aims to discuss several natural and synthetic methods which were used for manipulating bacterial quorum sensing.

Conclusion

The future challenge lies in the ability of the dental research to develop additional mechanisms for interfering with bacterial quorum sensing which can be used as preventive and therapeutic tools for combating oral polymicrobial diseases.

Clinical significance

This article aims at reviewing the literature and helping us to understand the ways of communication among bacteria in biofilms, which further open up the prospects in the treatment of diseases caused by biofilms.

How to cite this article

Biradar B, Devi P. Quorum Sensing in Plaque Biofilms: Challenges and Future Prospects. J Contemp Dent Pract 2011;12(6):479-485.
Intentional Replantation: A Procedure as a Last Resort
Authors: Jafarzadeh Hamid , Rouhani Armita , Javidi Babak , Habibi Morteza
Published: January 2012

Aim

To address the indications, contraindications, surgical procedure, complications following treatment, factors influencing the results and success rate of intentional replantation procedure.

Background

Intentional replantation is extraction of a tooth to do extraoral root canal therapy, curettage of apical lesion when present, and its replacement in its socket. It has been proposed as an alternative to routine extraction; however, it should be considered a last resort because the root may be fractured during extraction.

Results

The success rate of intentional replantation is far below than routine endodontic treatment or apical surgery. Difficultness of tooth extraction, the possibility of fracture during extraction and the risk of external resorption are some limitations of this treatment. The most common causes of failure in intentionally replanted teeth are external inflammatory resorption or replacement resorption and ankylosis caused by periodontal ligament damage.

Conclusion

The success rate up to 95% with an average retention of 3 to 5 years, has been reported.

Clinical significance

In some cases, endodontic retreatment or apical surgery is impossible or impractical. In these situations, intentional replantation may be considered as a last resort for preserving the tooth, so all clinicians should know about its indications/contraindications, surgical procedure and complications following treatment.

How to cite this article

Rouhani A, Javidi B, Habibi M, Jafarzadeh H. Intentional Replantation: A Procedure as a Last Resort. J Contemp Dent Pract 2011;12(6):486-492.
Treatment of Class II Division 1 Malocclusion with Myofunctional Trainer System in Early Mixed Dentition Period
Authors: Tripathi Nandini B , Patil Smita Nimbalkar
Published: January 2012

Dentofacial growth interferences, caused by abnormal lip and tongue function in the mixed dentition period are a common clinical condition. The main purpose of the treatment in such cases is to eliminate oral dysfunction, establish muscular balance and correct or diminish maxillary incisor protrusion. The position of the teeth is determined by the lip and tongue pressure. Lip function may have been the cause of forcing teeth in to malposition they occupy. The case report is presented where the myofunctional trainer T4K is used during growth phase.

How to cite this article

Tripathi NB, Patil SN. Treatment of Class II Division 1 Malocclusion with Myofunctional Trainer System in Early Mixed Dentition Period: J Contemp Dent Pract 2011;12(6):497-500.
Eddy turbulence, the double mesopause, and the double layer of atomic oxygen
Authors: Vlasov M. N. , Kelley M. C.
Published: January 2012

Abstract. In this study, we consider the impact of eddy turbulence on temperature and atomic oxygen distribution when the peak of the temperature occurs in the upper mesosphere. A previous paper (Vlasov and Kelley, 2010) considered the simultaneous impact of eddy turbulence on temperature and atomic oxygen density and showed that eddy turbulence provides an effective mechanism to explain the cold summer and warm winter mesopause observed at high latitudes. Also, the prevalent role of eddy turbulence in this case removes the strong contradiction between seasonal variations of the O density distribution and the impact of upward/downward motion corresponding to adiabatic cooling/heating of oxygen atoms. Classically, there is a single minimum in the temperature profile marking the location of the mesopause. But often, a local maximum in the temperature is observed in the height range of 85–100 km, creating the appearance of a double mesopause (Bills and Gardner, 1993; Yu and She, 1995; Gusev et al., 2006). Our results show that the relative temperature maximum in the upper mesosphere (and thus the double mesopause) can result from heating by eddy turbulence. According to our model, there is a close connection between the extra temperature peak in the mesosphere and the oxygen atom density distribution. The main feature of the O density height profile produced by eddy turbulence in our model is a double peak instead of a single peak of O density. A rocket experiment called TOMEX confirms these results (Hecht et al., 2004). Applying our model to the results of the TOMEX rocket campaign gives good agreement with both the temperature and oxygen profiles observed. Climatology of the midlatitude mesopause and green line emission shows that the double mesopause and the double layers of the green line emission, corresponding to the double O density height profile, are mainly observed in spring and fall (Yu and She, 1995; Liu and Shepherd, 2006). Further observations of the oxygen atom densities and the double mesopause would improve our understanding of the impact of turbulence on critical mesospheric parameters.
Annual emissions of CH4 and N2O, and ecosystem respiration, from eight organic soils in Western Denmark managed by agriculture
Authors: Petersen S. O. , Hoffmann C. C. , Schäfer C.-M. , Blicher-Mathiesen G. , Elsgaard L. , Kristensen K. , Larsen S. E. , Torp S. B. , Greve M. H.
Published: January 2012

Abstract. The use of organic soils by agriculture involves drainage and tillage, and the resulting increase in C and N turnover can significantly affect their greenhouse gas balance. This study estimated annual fluxes of CH4 and N2O, and ecosystem respiration (Reco), from eight organic soils managed by agriculture. The sites were located in three regions representing different landscape types and climatic conditions, and three land use categories were covered (arable crops, AR, grass in rotation, RG, and permanent grass, PG). The normal management at each site was followed, except that no N inputs occurred during the monitoring period from August 2008 to October 2009. The stratified sampling strategy further included six sampling points in three blocks at each site. Environmental variables (precipitation, PAR, air and soil temperature, soil moisture, groundwater level) were monitored continuously and during sampling campaigns, where also groundwater samples were taken for analysis. Gaseous fluxes were monitored on a three-weekly basis, giving 51, 49 and 38 field campaigns for land use categories AR, PG and RG, respectively. Climatic conditions in each region during monitoring were representative as compared to 20-yr averages. Peat layers were shallow, typically 0.5 to 1 m, and with a pH of 4 to 5. At six sites annual emissions of N2O were in the range 3 to 24 kg N2O-N ha−1, but at two arable sites (spring barley, potato) net emissions of 38 and 61 kg N2O-N ha−1 were recorded. The two high-emitting sites were characterized by fluctuating groundwater, low soil pH and elevated groundwater SO42− concentrations. Annual fluxes of CH4 were generally small, as expected, ranging from 2 to 4 kg CH4 ha−1. However, two permanent grasslands had tussocks of Juncus effusus L. (soft rush) in sampling points that were consistent sources of CH4 throughout the year. Emission factors for organic soils in rotation and with permanent grass, respectively, were estimated to be 0.011 and 0.47 g m−2 for CH4, and 2.5 and 0.5 g m−2 for N2O. This first documentation of CH4 and N2O emissions from managed organic soils in Denmark confirms the levels and wide ranges of emissions previously reported for the Nordic countries. However, the stratified experimental design also identified links between gaseous emissions and site-specific conditions with respect to soil, groundwater and vegetation which point to areas of future research that may account for part of the variability and hence lead to improved emission factors or models.
Avaliação da qualidade de vida dos estudantes de enfermagem segundo o Whoqol-Bref
Authors: Botti Nadja Cristiane Lappann , Cotta Eline Mascarenhas , Célio Fabiano De Almeida , Rodrigues Tatiana Aparecida , Araújo Marta Dantas de
Published: January 2012

ABSTRACT Objective: to evaluate the quality of life and to verify the level of satisfaction in the physical, psychological, social and environment among nursing student’s of the PUC Minas, campus Betim. Method: this is about a quantitative study, descriptive and exploratory done in the course of Nursing, in 2005, with a sample of 414 nursing student. Data were collected by questionnaire WHOQOL-Bref of World Health Organization. For the statistical analysis was used ANOVA and Newman-Keuls test (p
Infecção do Trato Urinário e Cateterismo Vesical: Aspectos Profiláticos e Laboratoriais
Authors: Kluczynik Caroline Evelin Nascimento , Solano Gabriela Beserra , Lima Martha Priscila Dantas de , Catão Raïssa Mayer Ramalho
Published: January 2012

ABSTRACTObjective: to check the prevalence of microorganisms isolated and described some procedures needed for prevention and diagnosis of urinary tract infections (UTI) when associated with bladder catheterization. Method: this is about a bibliographic study whose sources correspond to articles, books and manuals related to the theme. Results: the most prevalent organisms were Escherichia coli, Klebsiella sp. and Enterobacter sp. Conclusions: given the foregoing, it’s observed that the evaluation of these patients should be continuous, on suspicion of UTI the laboratorial exams should be prescribed and the samples should be collected by competent professional to facilitate and make more precise plan for the treatment of patients with this type of infection. Descriptors: infection; urinary tract; catheter; tests; laboratorial research.RESUMOObjetivos: verificar a prevalência dos microrganismos isolados e descrever alguns procedimentos necessários para prevenção e diagnóstico da infecção do trato urinário (ITU) quando associados ao cateterismo vesical. Métodos: este estudo tem cunho bibliográfico, suas fontes correspondem aos artigos, livros e manuais pertinentes ao tema. Resultados: os microrganismos mais prevalentes foram Escherichia coli, Klebsiella sp. e Enterobacter sp. Conclusão: diante do exposto, observa-se que a avaliação destes pacientes deve ser contínua, em suspeita de ITU os exames laboratoriais devem ser prescritos e as amostras devem ser coletadas por profissional competente, a fim de facilitar e tornar mais precisa o plano de tratamento do paciente com este tipo de infecção. Descritores: infecção; trato urinário; cateter; exames; investigação laboratorial.RESUMENObjetivo: verificar la prevalencia de los microorganismos aislados y describir algunos de los procedimientos necesarios para la prevención y diagnóstico en la infecciones del aparato urinario (IAU) cuando se asocian con el cateterismo vesical. Métodos: El estudio fue de naturaleza bibliográfica, a partir de artículos científicos, libros y manuales pertinentes al tema. Resultados: los organismos más prevalentes fueron Escherichia coli, Klebsiella sp. y Enterobacter sp. Conclusiones: Se observa que la avaluación de esos pacientes debe ser continua en los casos que se sospeche de infecciones urinarias, con prescripción de  exámenes de laboratorio, destacándose que las muestras  deben ser colectadas por profesionales competentes, para que el plano de tratamiento del paciente  sea precisa. Descriptores: infección; aparato urinario; catéter; investigación laboratorial.
A Fickian Approach for Wax Blooming from Vulcanized Rubber
Authors: Hoei Yoshio
Published: January 2012

The so-called “blooming” of additives in rubber is a general phenomenon of practical importance. Yet, it is still not fully understood and requires further investigation. Based on this, we have developed a more general kinetic model for blooming of a crystallizable additive in rubber. This model expects that it should be caused primarily by the melting of the crystal particles ascribed to local melting point depression, thereby occurring with a decrease in elastic stress induced around them. It can particularly determine an initial diffusion coefficient of the additive during blooming from data fitting. This was done using previously acquired literature data on certain vulcanizates with a wax, studied in a wide range of network densities. From the results obtained, the model is thought to be valid enough to explain the blooming mechanism.
Nonlinear Viscoelasticity of (Unvulcanized) Natural Rubber, Derived Materials, and Compounds Through LAOS Testing
Authors: Leblanc Jean L.
Published: January 2012

Natural rubber (NR) is by far the most important elastic material but its production specifications remain relatively poor when compared to synthetic elastomers. The so-called technically specified NR grades (i.e., technically specified rubber) are indeed characterized with respect to basic rubber test techniques, such as the Mooney viscosity, the (Wallace) plasticity (P0), and the Plasticity Retention Index, but high elasticity grades like ribbed smoked sheets are classified with respect to visual inspection criteria only. In addition, NR exhibits by nature more variation than synthetic polymers, owing to inevitable production differences from around 50 different clones of Hevea Brasiliensis, which are further enhanced by climate, soil, and other local effects, as well as seasonal effects on tapping. Most rubber processing operations occur at high rates of strain, and therefore it is essentially the nonlinear viscoelastic response of rubber materials that is of interest. This prompted the development of advanced investigation testing, such as large amplitude oscillatory strain (LAOS) experiments, which over the last decade were developed into powerful techniques to document the nonlinear viscoelastic behavior of polymer materials. First, the standard rheological tests for characterizing gum NR grades are briefly reviewed and discussed. Second, the equipment, test protocols, data treatment, and results modeling necessary to apply nonlinear viscoelastic testing are presented. Third, a number of LAOS experimental results obtained on various grades of NR, on a few chemically modified NR materials, and on two carbon black-filled NR compounds are reported and discussed.
Understanding Wet Skid Resistance Testing with the British Pendulum Skid Tester: Analysis of Sliding Noise from Various Filled Compounds
Authors: Pan Xiao-Dong , Zakelj Paul , Adams Cara , Neil Akiko , Chaplin Greg
Published: January 2012

The British pendulum skid tester (BPST) has been widely adopted for laboratory characterization of wet skid resistance (WSR) for rubber compounds. However, testing results are not yet well explained with material properties. For filled compounds made of the same styrene-butadiene rubber, on a Portland cement concrete surface wetted with water, WSR for compounds filled with inorganic oxides is higher than WSR for compounds filled with carbon black at the same filler volume fraction. However, such difference in WSR is eliminated under ethanol lubrication. Difference in WSR remains under ethanol lubrication between compounds filled with a reinforcing filler and compounds filled with a nonreinforcing filler. Accepting that dynamic deformation of rubber occurs in the frequency range between 103 and 106 Hz during testing with the BPST, loss tangent for the compounds is measured at various low temperatures but fails to correlate with WSR detected under water lubrication. Modification of bulk viscoelasticity from ethanol absorption should not be neglected for consideration of WSR under ethanol lubrication. During testing with the BPST, sliding noise generated by the assemblage of the spring and lever system in the pendulum with a rubber slider attached is captured under varied lubrication conditions. Both viscoelastic properties of rubber compounds and lubrication condition significantly affect sliding noise. However, no strict correlation between the intensity of sliding noise and WSR is observed. From frequency domain analysis, major components of the sliding noise lie in the frequency range between 500 and 5000 Hz for most compounds. For better understanding on testing with the BPST, modes of material deformation during dynamic sliding on a wet rough surface need to be further scrutinized.
Gender balance on boards: Stakeholders identification
Authors:   Departamento de Economía y Dirección de Empresas Universidad de Zaragoza Centro Politécnico Superior c/ María de Luna, 3 50018 Zaragoza. pluis@unizar.es, de Luis Carnicer Pilar , Bernal Cuenca Estrella ,   Departamento de Economía y Dirección de Empresas Escuela Universitaria de Estudios Empresariales Universidad de Zaragoza Edificio Lorenzo Normante María de Luna, s/n Zaragoza, 50018. bercue@unizar.es, Vela Jiménez María José ,   Departamento de Economía y Dirección de Empresas Escuela Universitaria de Estudios Empresariales Universidad de Zaragoza Edificio Lorenzo Normante María de Luna, s/n Zaragoza, 50018. mjvela@unizar.es, Pérez Pérez Manuela ,   Departamento de Economía y Dirección de Empresas Universidad de Zaragoza Centro Politécnico Superior c/ María de Luna, 3 50018 Zaragoza. manuela.perez@unizar.es.
Published: January 2012

Recent Spanish law and regulations have turned gender balance on Boards of Directors into a necessary element to manage in companies. The aim of this paper is to identify the stakeholders demanding such gender balance to companies, according to the Methodology of Mitchell et al. (1997) and Agle et al. (1999). The results sugest the shareholders are the most important group, so it seems that the financial goals continue being a priority. But we also observe that the Government is perceived as a very important stakeholder. Despite managers acknowledge the Government has a lot of power, its importance is explained by urgency and legitimacy attributes. This fact makes us doubting about the effectiveness of any development of a compulsory law, beyond the current one.
External Beam Radiation Therapy for PTFE Dialysis Grafts: A Pilot Study
Authors: Roy-Chaudhury Prabir , Duncan Heather J. , Zuckerman Darryl , Faiyaz Rashid , Munda Rino , Kant Shashi , Kelly Burnett , Narayana Ashwatha
Published: January 2012

Purpose

The aim of this study was to identify the effects of external beam radiation on PTFE dialysis graft dysfunction.

Methods

Seven patients who underwent PTFE dialysis graft angioplasty were randomized to receive either two 8 Gy doses of external beam radiation or no radiation. The primary endpoint was time to graft thrombosis with a secondary endpoint of time to first intervention.

Results

There was no statistically significant difference between the two groups in either of the endpoints, although grafts in the radiation group had a shorter time to thrombosis or intervention.

Conclusions

Our results demonstrate technical feasibility for use of external beam radiation in the setting of dialysis vascular access graft dysfunction. Larger randomized studies are required to identify whether there is a clinical benefit from this intervention.
Five Years of Vascular Access Stenosis Surveillance by Blood Flow Rate Measurements during Hemodialysis Using the Delta-H Method
Authors: Roca-Tey Ramón , Samon Rosa , Ibrik Omar , Roda Empar , González-Oliva Juan Carlos , Martínez-Cercós Román , Viladoms Jordi
Published: January 2012

Purpose

To report experience over five years of vascular access (VA) stenosis surveillance.

Methods

We prospectively monitored the blood flow rate (QA) of 145 VA in 131 ESRD (age 62.6 ±13.5 y) patients (pts). QA measurement: within the first hour of the hemodialysis (HD) session by the Delta-H method using the Crit Line III Monitor. All VA with baseline QA < 700 mL/min or decreased > 20% from baseline over time met the positive evaluation (PE) criteria and were referred for angiography (AG) plus elective intervention if stenosis ≥ 50%.

Results

We found 54 cases of PE in 47 VA; the AG was performed in 87% (47/54) cases of PE and most of them (43/47, positive predictive value: 91.5%) showed significant stenosis (mean degree 80.5 ±12.9%). Mean QA increased from 554.7±107.6 mL/min to 977.9 ± 359.9 mL/min just before versus after preventive intervention (P<.001). Without difference when comparing the highest QA reported before stenosis development (889.8 ± 409.5 mL/min) and the QA recorded just post-intervention (P=.18). Kt/V index: improved from 1.43 ± 0.22 to 1.49 ± 0.21 just before versus after intervention (P=.006).

Conclusions

1) The Delta-H technique is an accurate method for early diagnosis of VA stenosis and is useful in monitoring the hemodynamic effect of elective VA treatment. 2) After preventive intervention for stenosis, functional VA status is restored and HD delivery is improved.
Physiopathology of Overactive Bladder Syndrome
Authors: Sacco Emilio
Published: January 2012

The pathophysiology of OAB is complex, multifactorial and still largely unknown. Several pathophysiological mechanisms have been highlighted that may play a different role in different patient groups. There are now experimental evidences that support both the myogenic and neurogenic hypothesis, but in recent years the “integrative” hypothesis has been gaining more and more acceptance, where a disruption in the multiple interactions between different cell types (neurons, urothelium, interstitial cells, myocytes) and network functions represent a central element of lower urinary tract dysfunctions. Of utmost importance, a disorder in the urothelial sensory function and in the urothelial/suburothelial non-neural cholinergic system, favored by age and comorbidities, appears to be crucial for the development of the OAB. Neuroplastic and detrusor changes in OAB are broadly similar to those observed in bladders exposed to outlet obstruction, neuropathies, inflammation or aging, and may be driven by a common urothelial dysfunction. Several signaling substances and their receptors were found to be involved in central pathways of bidirectional communication between the different cell types in the bladder, and were shown to be modified in several animal models of OAB as well as in human models, indicating new potential therapeutic targets.
Effects of Replacing Groundnut Cake with Blood Vegetable Waste Meal in the Diets of Weaner Rabbits
Authors: Adeniji Adedayo Abiodun
Published: January 2012

A total of seventy-two weaner rabbits of eight weeks of age were used to assess the effects of replacing groundnut cake (GNC) with blood vegetable waste meal (BVWM) in the diets of rabbits. The BVWM was fed to replace dietary GNC at 0, 15, 30, and 45%, with GNC being 15% in the control diet. The four experimental diets were fed ad libitum for a period of eight weeks. BVWM was analyzed to contain a crude protein value of 62.35%. There were comparable feed intake values by rabbits on all the diets although the rabbits in the higher replacement levels of BVWM tended to have consumed more of the feed. There were significant increases (P<0.05) in body weight gain by rabbits as the BVWM level increased in the diet. Similarly, the feed to gain ratio improved and nitrogen digestibility increased (P<0.05) with higher levels of BVWM in the diet. This study shows that rabbits can tolerate the 45% BVWM replacement of groundnut cake effectively.
Time in e-Learning Research: A Qualitative Review of the Empirical Consideration of Time in Research into e-Learning
Authors: Barbera Elena , Clarà Marc
Published: January 2012

Time has been argued by several influential approaches as essential for understanding learning and teaching processes. In e-learning, however, the traditional time limits of such processes are modified, which implies challenges and possibilities for e-learning research. This paper is aimed at understanding how time is included in empirical e-learning research literature. With this aim in mind, the paper presents a qualitative review of 24 e-learning papers. Five issues are analysed: the conception of time, its inclusion in an explicative model, its inclusion in the research process, the analytical units, and the data used in the study of time. Based on our analysis, we discuss some implications and potentialities for e-learning research on the relations between time and learning.
Carbon nanofiber paper and its effect on cure kinetics of low temperature epoxy resin
Authors: Movva Siva , Ouyang Xilian , Castro Jose , Lee L. James
Published: January 2012

In this study, the preparation, properties, and characterization of thin films or “nanopapers” of carbon nanofibers (CNFs) were studied. Specifically, a layer‐by‐layer nanopaper preparation method was used, which significantly improved the mechanical properties of nanopapers. The effect of CNF nanopaper on the cure kinetics of a low temperature epoxy resin was studied. A modified autocatalytic model was used to represent the reaction kinetics. It was found that the presence of CNF nanopaper substantially increased the resin reaction rate and final conversion. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Effect of welding parameters on the heat affected zone and the mechanical properties of friction stir welded poly(ethylene‐terephthalate‐glycol)
Authors: Kiss Z. , Czigány T.
Published: January 2012

The bond strength and the heat affected zone (HAZ) of friction stir welded seams made of poly(ethylene‐terephthalate‐glycol) are analyzed in the article. The seams were prepared with various settings (rotation speed and feeding rate) and with various welding tools. Using the welding parameters (rotation speed, the feed rate, and the tool diameter) a K‐factor characterizing the welding process was defined. The novel K factor is related to the welding heat input, which is in direct correlation with both the range of the HAZ and the mechanical properties of the seam. The HAZ formed was analyzed by stress optical method, the mechanical properties by flexural test. It has been demonstrated that the efficiency factor of the welded joint is closely related to the width of the HAZ and it depends on the welding parameters and the tools. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Relationship between tensile properties and ballistic performance of poly(ethylene naphthalate) woven and nonwoven fabrics
Authors: Afshari Mehdi , Chen Peng , Kotek Richard
Published: January 2012

In this study, we investigated the effect of tensile properties of poly(ethylene naphthalate) (PEN) yarns on the ballistic performance of woven and nonwoven soft and composite armors. The results of ballistic tests of PEN armors were compared with Kevlar 49 armors as a reference. Based on these results, the Cunniff's equation was revised by removing the fiber elongation at break to predict the relationship between tensile properties and ballistic performances of PEN fibers. The calculations showed that by increasing tenacity of PEN fibers from 8.5 g/den (commercial product) to 12.5 g/den (strongest up to date PEN fibers produced by a novel melt spinning process discovered by our research group), the weight ratio of PEN to Kevlar 49 decreased from 1.8 to 1.35 with the same ballistic performance. Contrary to the results of the soft armors, composite armors made of high modulus PEN woven fabric showed a 17% lower ballistic resistance compared to the composite armor made of low modulus PEN woven fabric. The results of ballistic tests indicated that high tenacity PEN fibers produced in this research could have potential in soft and composite armors, and high velocity impact applications or improve performance of PEN in its current applications. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Silver‐coated wool yarns with durable antibacterial properties
Authors: Pollini M. , Paladini F. , Licciulli A. , Maffezzoli A. , Nicolais L. , Sannino A.
Published: January 2012

The use of fabrics with antibacterial properties for commodity applications can provide numerous advantages such as a reduction in the release of odors due to bacterial proliferation in sweat and a reduction in the development of skin hypersensitivity reactions due to microorganisms trapped into the fabrics. Silver is one of the most effective antibacterial agents used for the high degree of biocompatibility and for its long‐term antibacterial effectiveness against many different bacterial strains. In this study, an innovative technique for the deposition of nanosilver antibacterial coating on woolen fiber was analyzed. In particular, fabrics woven with different percentages of silver‐treated fibers were compared to determine the best ratio preserving the antibacterial activity and optimizing the cost‐effectiveness of the final product. Scanning electron microscopy revealed a uniform distribution of silver nanoclusters on the fibers. The impressive silver coating stability and durability were demonstrated after several washing cycles through thermogravimetric analysis. The antimicrobial activity of the silver‐treated substrates was evaluated by antibacterial tests onEscherichia coli. A very strong antibacterial activity was found even in presence of the lower silver content; therefore, a blend of coated and uncoated fibers is proposed for practical applications. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Curing octaepoxysilsesquioxane with different curing agents
Authors: Zhang Zengping , Liang Guozheng , Fang Changqing , Pei Jianzhong , Chen Shuanfa
Published: January 2012

Octaepoxysilsesquioxane (POSS‐Ep) was first synthesized by the hydrolysis and condensation of γ‐[(2,3)‐epoxypropoxy]propyltrimethoxysilicane (KH‐560) with the presence of ethanol and HCl at 55°C for 72 h. Then, it was cured with 4,4′‐diaminodiphenylsulfone (DDS) and methylnadic anhydride (MNA), respectively. The curing reactions between POSS‐Ep and DDS or MNA were investigated by FTIR. Thermal stability of the cured nanocomposites was studied by TGA. The micromophologies of the obtained hybrids were observed by SEM. FTIR results show that POSS‐Ep can be cured completely with DDS or MNA to obtain the final organic–inorganic (O–I) hybrids after the same experimental curing cycle: 120°C/2 h + 140°C/2 h + 160°C/2 h + 180°C/2 h + 200°C/2 h. TGA results show that POSS‐Ep/DDS hybrid displays better thermal stability than that of POSS‐Ep/MNA hybrid. Initial thermal degradation temperature (Tdi) of POSS‐Ep/DDS hybrid is 420°C, 195°C higher than that of POSS‐Ep/MNA (225°C). SEM images of the fracture surfaces of the hybrids suggest the cured POSS‐Ep possesses good mechanical properties. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Correlation between viscoelasticity, microstructure, and molecular properties of zein and pennisetin melts
Authors: Gómez‐Martínez D. , Altskär A. , Stading M.
Published: January 2012

Cereals are a large source of biopolymers, where mainly the starch is used for food and feed. A rapidly growing cereal application is the production of biofuel, mainly produced from corn in the US. The starch is fermented to ethanol leaving spent grain rich in cereal proteins as a by‐product. The corn protein zein is currently extracted on a large scale and used in, for example, material applications. Similarly, pennisetin can be extracted from pearl millet, a crop critical for food security in sub‐Saharan Africa. The formation of viscoelastic melts is crucial for (bio)plastics production and the viscoelasticity, microstructure, and molecular properties of zein and pennisetin melts were determined here. The proteins were mixed with plasticizers (polyethyleneglycol or glycerol/citric acid) to form melts. The melts displayed a phase separated microstructure with protein‐rich and plasticizer‐rich regions with distinctly separate Tgs. The pennisetin melts formed cross‐links at temperatures above 60°C, which could be related to the high content of cysteine and methionine, as compared to zein. As a consequence, pennisetin melts showed a more thermocomplex behavior than zein melts. For zein melts, the mixture of glycerol and citric acid interacted with protein in addition to being a plasticizer causing a high‐molecular weight shoulder in the molecular weight distribution. The study showed that, although both zein and pennisetin form viscoelastic melts, the choice of plasticizer strongly affects both melt structure and physical properties. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012