bluuebunny/crossref_metadata_2025 huggingface dataset:
Carbon-Based Solar Cell from Amorphous Carbon with Nitrogen Incorporation
Authors: Fadzilah A.N. , Kamaruzaman Dayana , Rusop Mohamad
Published: October 2012

Nitrogen doped amorphous carbon (n-C:N) solar cells were successfully prepared using a simple and low cost Chemical Vapor Deposition (CVD) method using camphor oil as a precursor. Four samples of n-C:N were deposited by varying the deposition temperature (500oC, 550oC, 600oC, 650oC). The fabricated solar cell using n-C:N with the configuration of Au/n-C:N/p-Si/Au achieved an increasing efficiency as temperature increase (0.000202% to 0.001089%). As a reference, pure a-C was deposited at 500oC and exhibit 0.000048% efficiency. The current-voltage (I-V) graph emphasized on the linear graph (ohmic) for the a-C thin films, whereas for the p-n device structure, a rectifying curve was obtained. Electrical conductitivity possesses increasing value (1.69 x 10-2 to 22 Ω-1 cm-1) due to increasing sp2 ratio in a-C as temperature increase. The rectifying curves signify the heterojunction between the n-doped a-C film and the p-Si substrate and designate the generation of electron-hole pair of the samples under illumination. Photoresponse characteristics of the deposited a-C was highlighted when being illuminated (AM 1.5 illumination: 100 mW/cm2, 25oC) and optical band gap for the nitrogen doped a-C is reported from 0.75 eV to 0.25 eV as temperature increase.
Residual Stresses and Deformations in Electron Beam Melting process Using Finite Element Analysis
Authors: Hosseini Afshin Mohammad , Masood Syed H. , Fraser Darren , Jahedi Mahnaz
Published: October 2012

The simulation of residual stress in Electron Beam Melting (EBM) process is critical for optimization of process conditions. However, there is no published literature on the simulation of residual stresses in this process. This paper considers finite element modeling of the temperature distribution through transient thermal analysis. The measured temperature and total heat flux from transient thermal analysis are then used as initial input parameters to the structural analysis. Consequently, deformations and residual stresses in structural analysis were measured. The titanium alloy, Ti6Al4V has been used, which is one of the most common materials for biomedical implants due to its high strength to weight ratio, corrosion resistance, and its biocompatibility features.
Analytical Calculation of the True Equivalent Chip Thickness for Cutting Tools and its Influence on the Calculated Tool Life
Authors: Ståhl Jan Eric , Schultheiss Fredrik
Published: October 2012

A majority of the established systems for determination and optimization of cutting data are based on Woxén’s equivalent chip thickness, heW. In metal cutting theory and models, the equivalent chip thickness is of vital importance when the depth-of-cut ap is in the same order or smaller than the nose radius r. Woxén made considerable simplifications in his chip area model, that form the basis for calculations of the equivalent chip thickness. Basic mathematical solutions, e.g. describing the chip area on circular inserts, are lacking. This article describes the geometrical implications when machining with round inserts. The error in Woxén’s equivalent chip thickness is largest when the depth-of-cut is less than ¼ of the nose radius and are up to 40 % wrong for some combinations of cutting data in the finishing range. The presented results explain the difficulties in getting a good validity in the models used to calculate tool life in finishing machining. The error leads to an underrating of the tool load in many machining situations
Prediction of Cutting Temperatures by Using Back Propagation Neural Network Modeling when Cutting Hardened H-13 Steel in CNC End Milling
Authors: Adesta Erry Yulian Triblas , Al Hazza Muataz H.F. , Suprianto M.Y. , Riza Muhammad
Published: October 2012

Machining of hardened steel at high cutting speeds produces high temperatures in the cutting zone, which affects the surface quality and cutting tool life. Thus, predicting the temperature in early stage becomes utmost importance. This research presents a neural network model for predicting the cutting temperature in the CNC end milling process. The Artificial Neural Network (ANN) was applied as an effective tool for modeling and predicting the cutting temperature. A set of sparse experimental data for finish end milling on AISI H13 at hardness of 48 HRC have been conducted to measure the cutting temperature. The artificial neural network (ANN) was applied to predict the cutting temperature. Twenty hidden layer has been used with feed forward back propagation hierarchical neural networks were designed with Matlab2009b Neural Network Toolbox. The results show a high correlation between the predicted and the observed temperature which indicates the validity of the models.
Klaagliedere by Qumran: ’n Tweede redaksie?
Authors: Van Rooy Herrie F.
Published: October 2012

Lamentations at Qumran: A second edition? The four Qumran manuscripts of Lamentations presented the Hebrew text of the book from a period of about one hundred years before the standardisation of the Hebrew consonantal text. These manuscripts were studied to answer the question whether they, or one or more of them, presented a different edition of the Hebrew text than the one preserved in the Masoretic Text. The current consensus is that the Masoretic Text was well preserved and that the ancient versions, the Septuagint, Targum, Peshitta and Vulgate, were translated from Hebrew texts close to the Masoretic tradition. The four manuscripts were firstly described in this article. They all dated from the last part of the first century BCE. They were then studied in detail with regard to the variants they contain, their agreement with the Masoretic Text and the ancient versions. Only a few parts of 3QLam and 5QLamb had been preserved. These sections agreed mostly with the Masoretic Text, but no definite conclusions could be made on account of their bad state of preservation. 4QLama agreed frequently with the Masoretic Text where one or more of the versions disagreed from it. 4QLam did not agree often with the Masoretic Text when it differed from the ancient versions, but frequently went its own way. These manuscripts contained a number of variants pointing to a different edition of the book. The most important variants occurred in Lamentations 1:7, 13, 14 and 16. The different order of verses 16 and 17 against the Masoretic Text was also important in this regard. This manuscript pointed to a different textual tradition than the one occurring in the Masoretic Text.
Inversion of the Radon Transform on the Free Nilpotent Lie Group of Step Two
Authors: He Jianxun , Xiao Jinsen
Published: October 2012

Let F2n;2 be the free nilpotent Lie group of step two on 2n generators, and let P denote the affine automorphism group of F2n;2. In this article the theory of continuous wavelet transformon F2n;2 associated with P is developed, and then a type of radial wavelet is constructed. Secondly, the Radon transform on F2n;2 is studied, and two equivalent characterizations of the range for Radon transform are given. Several kinds of inversion Radon transform formulae are established. One is obtained from the Euclidean Fourier transform; the others are from the group Fourier transform. By using wavelet transforms we deduce an inversion formula of the Radon transform, which does not require the smoothness of functions if the wavelet satisfies the differentiability property. In particular, if n = 1, F2;2 is the 3-dimensional Heisenberg group H1, the inversion formula of the Radon transform is valid, which is associated with the sub-Laplacian on F2;2. This result cannot be extended to the case n ≥ 2.
Avaliação da Força Muscular e Capacidade Respiratória em Pacientes com Síndrome de Down Após Bad Ragaz
Authors: Castoldi Anieli , Périco Eduardo , Grave Magali
Published: October 2012

Introdução. Síndrome de Down é uma síndrome cromossômica re­sultante da trissomia do cromossomo 21, causando em seus portadores hipotonia, redução de força muscular, frouxidão ligamentar e retardo mental. Objetivo. verificar possíveis alterações na força muscular e na capacidade respiratória de pacientes com Síndrome de Down subme­tidos ao método hidroterapêutico de Bad Ragaz. A amostra foi com­posta por 54 indivíduos com Síndrome de Down, com idades entre 16 a 31 anos. Método. as avaliações e a intervenção hidroterapêutica ocorreram em dez encontros. No 1º e no 10º encontros, foram realiza­das as avaliações da força muscular através do Teste Muscular Manual e da força muscular respiratória com Manovacuômetro. Nos demais foram aplicadas técnicas do método hidroterapêutico de Bad Ragaz. Para comparar as diferenças entre o início e o final do tratamento foi aplicado o teste t para amostras comparadas. Resultados. ocorreram diferenças significativas nos pacientes, antes e após a intervenção, para os seguintes parâmetros testados: extensores de tronco e ombro, abdu­tores de ombro, flexores de cotovelo, extensores de cotovelo, flexores de quadril, extensores de joelho e pressão expiratória máxima. Con­clusão. o método de Bad Ragaz se mostrou eficiente para aumento da força muscular e respiratória para a maioria dos parâmetros testados.
Smokeless Tobacco Use Following Smoking Bans in Bars
Authors: Adams Scott , Cotti Chad D. , Fuhrmann Daniel M.
Published: October 2012

We test for a unique form of compensatory behavior among smokers who wish to continue their nicotine consumption following the smoking bans placed on bars. We find a substantial increase in smokeless tobacco use among smokers, particularly those who drink and are of typical bar‐going age. We also find that everyday smokers, who clearly have the strongest nicotine dependence, are more likely to increase smokeless‐tobacco use than occasional smokers are.
Audiovestibular Test Battery Approach in Patients with Vertigo
Authors: Valame Deepa A , Nandapurkar Preeti
Published: October 2012

All audiological tests are site-of-lesion tests and are used as a part of a test battery. Pure tone audiometry gives estimate of peripheral hearing status. Speech audiometry, acoustic reflex testing and auditory brain stem response differentiate cochlear and retrocochlear sites of lesion. Addition of cervical vestibular evoked myogenic potentials (VEMP) and ocular VEMP to this battery can further differentiate between saccular vs utricular lesions and between lesions of inferior vs superior vestibular nerve. Overall, this battery of tests provides useful insights into the otoneurological diagnosis of vertigo. Few case examples are cited to elucidate the utility of audiovestibular test battery.

How to cite this article

Valame DA, Nandapurkar P. Audiovestibular Test Battery Approach in Patients with Vertigo. Int J Otorhinolaryngol Clin 2012;4(1):5-16.
Benign Paroxysmal Positional Vertigo and Positional Vertigo Variants
Authors: Libonati Giacinto Asprella
Published: October 2012

This article reviews the causes of positional vertigo and positional nystagmus of peripheral origin. Benign paroxysmal positional vertigo is described in all its variants, its diagnosis and therapy are highlighted. In addition, nonparoxysmal positional vertigo and nystagmus due to light/heavy cupula of lateral and posterior semicircular canal is focused on. The differential diagnosis between positional vertigo due to otolithic and nonotolithic causes is discussed.

How to cite this article

Asprella Libonati G. Benign Paroxysmal Positional Vertigo and Positional Vertigo Variants. Int J Otorhinolaryngol Clin 2012;4(1):25-40.
Vertigo in Cerebrovascular Diseases
Authors: Chakor Rahul T , Eklare Nishikant
Published: October 2012

Background

Vertigo as a symptom of cerebrovascular disease is relatively uncommon. All types of cerebrovascular diseases namely ischemia, infarction, hemorrhage can produce vertigo. Since, cerebrovascular disease is an emergency prompt recognition and treatment is necessary to prevent neurologic deficit and death. Among cerebrovascular diseases vertebrobasilar territory strokes commonly present with vertigo. Since, the term vertigo is used nonspecifically by patients this may lead to delay in diagnosis of these strokes. This article reviews the epidemiology of vertigo in cerebrovascular diseases and the various stroke syndromes associated with vertigo.

Cerebrovascular diseases in the vertebrobasilar territory have vertigo, imbalance, dizziness in addition to other symptoms and signs. Posterior inferior cerebellar artery, anterior inferior cerebellar artery, superior cerebellar artery and basilar artery territory strokes can present with true vertigo. A high index of suspicion of stroke in patients with vertigo and risk factors for stroke is essential. Other vascular causes of vertigo are small cerebellar hemorrhage, vestibular cortex stroke, rotational vertebral artery syndrome, transverse/sigmoid sinus thrombosis and vestibular paroxysmia.

Conclusion

Cerebrovascular disorders are estimated to account for 3 to 4% of patients with vertigo or dizziness. Early detection and treatment is necessary to prevent disability and death in these cases of vascular vertigo.

How to cite this article

Chakor RT, Eklare N. Vertigo in Cerebrovascular diseases. Int J Otorhinolaryngol Clin 2012;4(1):46-53.
Vestibular Rehabilitation: An Overview
Authors: Writer HS , Arora RD
Published: October 2012

The approach in management of dizziness and disequilibrium is multidisciplinary. However, the emphasis is on function. Management models based on pathology alone may not provide the desired outcome as patients with similar pathologies will present with significant differences in impairments and functional limitations. Because of these differences, patients with similar pathologies may not respond the same to a given treatment. Both pathology and impairment information is essential for effective treatment planning. This article gives an overview of vestibular rehabilitation emphasizing on management models utilising treatment plans customized to individual patient's impairments. It briefly describes the anatomy and physiology of the motion sensors and its connections, explains the physiological basis of recovery from vestibular dysfunction and emphasizes the importance of history taking and examination to delineate impairments that cause activity limitation and participatory restrictions. Machine-based assessment may be used to quantify impairments. Use of equipments for rehabilitation shows good outcome but may not always be cost effective. Physiotherapists dealing with balance disorders are proficient in making a functional diagnosis to improve patient's balance and mobility tasks for safe and effective function in their daily life.

How to cite this article

Writer HS, Arora RD. Vestibular Rehabilitation: An Overview. Int J Otorhinolaryngol Clin 2012;4(1):54-69.
Riparian zone hydrology and soil water total organic carbon (TOC): implications for spatial variability and upscaling of lateral riparian TOC exports
Authors: Grabs T. , Bishop K. , Laudon H. , Lyon S. W. , Seibert J.
Published: October 2012

Abstract. Groundwater flowing from hillslopes through riparian (near-stream) soils often undergoes chemical transformations that can substantially influence stream water chemistry. We used landscape analysis to predict total organic carbon (TOC) concentration profiles and groundwater levels measured in the riparian zone (RZ) of a 67 km2 catchment in Sweden. TOC exported laterally from 13 riparian soil profiles was then estimated based on the riparian flow–concentration integration model (RIM). Much of the observed spatial variability of riparian TOC concentrations in this system could be predicted from groundwater levels and the topographic wetness index (TWI). Organic riparian peat soils in forested areas emerged as hotspots exporting large amounts of TOC. These TOC fluxes were subject to considerable temporal variations caused by a combination of variable flow conditions and changing soil water TOC concentrations. Mineral riparian gley soils, on the other hand, were related to rather small TOC export rates and were characterized by relatively time-invariant TOC concentration profiles. Organic and mineral soils in RZs constitute a heterogeneous landscape mosaic that potentially controls much of the spatial variability of stream water TOC. We developed an empirical regression model based on the TWI to move beyond the plot scale and to predict spatially variable riparian TOC concentration profiles for RZs underlain by glacial till.
Cascading climate effects and related ecological consequences during past centuries
Authors: Naef-Daenzer B. , Luterbacher J. , Nuber M. , Rutishauser T. , Winkel W.
Published: October 2012

Abstract. The interface between climate and ecosystem structure and function is incompletely understood, partly because few ecological records start before the recent warming phase. Here, we analyse an exceptional 100-yr long record of the great tit (Parus major) population in Switzerland in relation to climate and habitat phenology. Using structural equation analysis, we demonstrate an uninterrupted cascade of significant influences of the large-scale atmospheric circulation (North-Atlantic Oscillation, NAO, and North-sea – Caspian Pattern, NCP) on habitat and breeding phenology, and further on fitness-relevant life history traits within great tit populations. We then apply the relationships of this analysis to reconstruct the circulation-driven component of fluctuations in great tit breeding phenology and productivity on the basis of new seasonal NAO and NCP indices back to 1500 AD. According to the structural equation model, the multi-decadal oscillation of the atmospheric circulation likely led to substantial variation in habitat phenology, productivity and consequently, tit population fluctuations with minima during the "Maunder Minimum" (∼ 1650–1720) and the Little Ice Age Type Event I (1810–1850). The warming since 1975 was not only related with a quick shift towards earlier breeding, but also with the highest productivity since 1500, and thus, the impact of the NAO and NCP has contributed to an unprecedented increase of the population. A verification of the structural equation model against two independent data series (1970–2000 and 1750–1900) corroborates that the retrospective model reliably depicts the major long-term NAO/NCP impact on ecosystem parameters. The results suggest a complex cascade of climate effects beginning at a global scale and ending at the level of individual life histories. This sheds light on how large-scale climate conditions substantially affect major life history parameters within a population, and thus influence key ecosystem parameters at the scale of centuries.
Recirculation in the Fram Strait and transports of water in and north of the Fram Strait derived from CTD data
Authors: Marnela M. , Rudels B. , Houssais M.-N. , Beszczynska-Möller A. , Eriksson P. B.
Published: October 2012

Abstract. The volume, heat and freshwater transports in the Fram Strait are estimated from geostrophic computations based on summer hydrographical data from 1984, 1997, 2002 and 2004. In these years, in addition to the usually sampled section along 79° N, a section between Greenland and Svalbard was sampled further north. Quasi-closed boxes bounded by the two sections and Greenland and Svalbard can then be formed and conservation constraints applied on the boxes. The net volume flux is southward and varies between 2 and 4 Sv. The recirculation of Atlantic water is about 2 Sv. Heat is lost to the atmosphere and the heat loss averaged for the four boxes is about 10 TW and the net heat (temperature) transport is 20 TW northward into the Arctic Ocean, with large interannual differences. The mean net freshwater added between the sections is 40 mSv and the mean freshwater transport southward across 79° N is less than 60 mSv, indicating that most of the liquid freshwater leaving the Arctic Ocean through Fram Strait in summer derives from sea ice melt in the northern vicinity of the strait. In 1997, 2001 and 2003 meridional sections along 0° longitude were sampled and in 2003 two smaller boxes can be formed, and the recirculation of Atlantic water in the strait is estimated by geostrophic computations and continuity constraints. The recirculation is weaker close to 80° N than close to 78° N, indicating that the recirculation is mainly confined to south of 80° N. This is supported by the observations in 1997 and 2001, when only the northern part of the meridional section, from 79° N to 80° N, can be computed with the constraints applied. The recirculation is found strongest close to 79° N.
Reflection: A Key Component to Thinking Critically
Authors: Colley Binta M , Bilics Andrea R , Lerch Carol M
Published: October 2012

The ability to think critically is an important trait of all members of society. With today’s multinational, multicultural, complex issues, citizens must be able to sift through large amounts of various data to make intelligent decisions. Thinking critically must be a focus of higher education in order to provide the intellectual training for its students to participate in this world. This qualitative study examined critical reflection through student writing as seen in three different college settings. Structured reflections were analyzed using Marzano’s New Taxonomy of Educational Objectives (2001).
La capacité d’exercer son esprit critique est une caractéristique importante de tous les membres de la société. De nos jours, les enjeux sont multinationaux, multiculturels et complexes. Les citoyens doivent être capables de filtrer de grandes quantités de données diverses pour prendre des décisions intelligentes. L’enseignement supérieur doit être axé sur la pensée critique afin de procurer aux étudiants la formation intellectuelle qui leur permettra de participer au monde qui les entoure. La présente étude qualitative se penche sur la réflexion critique dans les écrits des étudiants de trois différents collèges. Les chercheurs ont analysé les réflexions structurées à l’aide de la nouvelle taxonomie des objectifs pédagogiques de Marzano (2001).
Growth Performance of the Mudfish, Clarias anguillaris (Pellegrin, 1923) in Treated and Untreated Domestic Sewage
Authors: Nwabueze Agatha A
Published: October 2012

Growth of the mudfish, Clarias anguillaris in of treated and untreated domestic sewage was investigated. Six weeks old fingerlings obtained from Delta State University, Asaba Campus Research Farm were used and the study lasted for 14 weeks. Fingerlings were kept in stock tank containing 10, 000 cm3 bore hole water and allowed to acclimate for two weeks. The stock tank was well aerated and fingerlings fed twice daily at the rate of 4% body weight with poultry mash in a daily renewal static bioassay system. The stock (0%- control) was then diluted with bole hole water serially to give 25, 50, 75 % strength of the treated and untreated domestic sewage and 100 % into which 10 fingerlings each were introduced. Weekly measurement of growth parameters of fish total length and weight were taken. The condition factor (k) was calculated. Increase in fish total length and weight in control, treated and untreated domestic sewage was observed. Growth of fish was significantly higher (P<0.05) in the treated domestic sewage than in the untreated. There was no significant (P>0.05) difference in total length of fish in all concentrations of treated domestic sewage as compared with controls. However, fish in 100% concentration of domestic sewage had a slower increase in total length than fish in other treated concentrations. Weight gain in C. anguillaris was higher in the 50% but not significantly (P>0.05) higher than other concentrations of treated domestic sewage. The increase in fish weight in the untreated domestic sewage was not significantly (P>0.05) different in all the treatments but was significantly (P<0.05) lower than that of fish in the control. Condition factor of C. anguillaris in both the treated and untreated domestic sewage varied and decreased except for fish in 100% treated domestic sewage which was observed to have an increase in the value of the condition factor from 3.76g cm-3 to 4.73g cm-3. Untreated domestic sewage water showed a higher turbidity, biochemical Oxygen Demand (B.O.D), alkalinity and nitrate composition of than treated sewage which had higher oxygen content and was clearer in appearance than the untreated. Microbial analysis shows the presence of Escherichia fecalis, Streptococcus fecalis and Enterococcus fecalis in untreated sewage with ciliated protozoans in both treated and untreated sewage. This study has shown that treated domestic sewage is best for healthy fish growth with reduced risk of transfer of pathogens.
Cytology and Human Papillomavirus Screening Test Results Associated With 2827 Histopathologic Diagnoses of Cervical Intraepithelial Neoplasia 2/3
Authors: Zhao Chengquan , Amin Milon , Weng Baoying , Chen Xiangbai , Kanbour-Shakir Amal , Austin R. Marshall
Published: October 2012

Context.—Cervical screening in the United States increasingly involves newer US Food and Drug Administration–approved cytologic methods and adjunctive high-risk human papillomavirus (hrHPV) DNA testing.

Objective.—To document cervical screening test performance preceding histopathologic cervical intraepithelial neoplasia (CIN) 2/3 diagnoses.

Design.—Preceding screening test results with computer-imaged, liquid-based cytology (LBC) and hrHPV results were analyzed for 2827 patients with histopathologic CIN 2/3 diagnoses.

Results.—Of 2827 patients with CIN 2/3 diagnoses, 2074 (73.4%) had system LBC findings within 4 months of CIN 2/3 diagnoses: high-grade squamous intraepithelial lesion (n = 862; 41.6%), low-grade squamous intraepithelial lesion (n = 464; 22.4%), atypical squamous cells of undetermined significance (n = 445; 21.5%), atypical squamous cells, cannot exclude high-grade squamous intraepithelial lesion (n = 288; 13.9%), and atypical glandular cells/adenocarcinoma in situ (n = 15; 0.7%). Of the 2827 patients, 1488 (52.6%) also had earlier system LBC results at more than 4 months to 3 years before CIN 2/3 diagnoses: one or more abnormal LBC results (n = 978; 65.7%), one or more negative LBC results (n = 911; 61.2%), both abnormal and negative LBC (n = 401; 26.9%). Of 807 patients with hrHPV cotest results within 4 months of CIN 2/3 diagnoses, 786 (97.4%) had hrHPV+ results. Of 454 patients who also had earlier hrHPV results at more than 4 months to 3 years before CIN 2/3 diagnoses: 377 (83.0%) had one or more hrHPV+ result, 110 (24.2%) had one or more hrHPV− result, and 33 (7.3%) had both positive and negative HPV results.

Conclusion.—Patients with histopathologic CIN 2/3 had recent abnormal LBC results, most often, high-grade squamous intraepithelial lesions. Among cotested patients, 97.4% (786 of 807) tested hrHPV+. However, a significant number of patients tested during an extended period of several years had earlier negative Papanicolaou or negative HPV test results, suggesting the recent development of some CIN 2/3 lesions and supporting the value of cotesting for enhanced detection of other developing, small, inaccessible, or nondiagnostic precursor lesions.
Development and Evaluation of a Teaching Guide in English Plus
Authors: Gilbas Sherill A. , Detera Tarcela F. , Deri Ritzelda A. , Remolacio Ryan D. , Manga Annabell
Published: October 2012

The study devised a teacher-made test to identify the needs and difficulties of the students in English Plus and the results were utilized to revise and enrich the syllabus. The descriptive – evaluative method was employed in this research. A teacher-made test was administered to 200 students selected by random sample. Content analysis of the syllabi of the professors and instructors were used as basis in constructing the teacher-made test. The areas under the English Proficiency Test in the SSC Admission Test were also considered. Results of the study revealed that naming words, word groups and paragraph organization are areas with performance level (PL) of 0-49 and are considered as difficult while areas like vocabulary, modifiers and verbs with (PL) of 50-75 are considered as nearly difficult. These results are the basis of the revised and enriched syllabus. It is concluded that almost all competencies in the areas cited were all considered as needs and difficulties of the English Plus students. Thus, there is the need for the inclusion of these competencies in the syllabus and an outline of a teaching guide.   Keywords - Teaching guide, English plus, syllabus
Sequencing of rhesus macaque Y chromosome clarifies origins and evolution of the DAZ (Deleted in AZoospermia) genes
Authors: Hughes Jennifer F. , Skaletsky Helen , Page David C.
Published: October 2012

Studies of Y chromosome evolution often emphasize gene loss, but this loss has been counterbalanced by addition of new genes. The DAZ genes, which are critical to human spermatogenesis, were acquired by the Y chromosome in the ancestor of Old World monkeys and apes. We and our colleagues recently sequenced the rhesus macaque Y chromosome, and comparison of this sequence to human and chimpanzee enables us to reconstruct much of the evolutionary history of DAZ. We report that DAZ arrived on the Y chromosome about 38 million years ago via the transposition of at least 1.1 megabases of autosomal DNA. This transposition also brought five additional genes to the Y chromosome, but all five genes were subsequently lost through mutation or deletion. As the only surviving gene, DAZ experienced extensive restructuring, including intragenic amplification and gene duplication, and has been the target of positive selection in the chimpanzee lineage.

Editor's suggested further reading in BioEssays Should Y stay or should Y go: The evolution of non‐recombining sex chromosomes Abstract
Bacteriophage‐induced aggregation of oil sands tailings
Authors: Curtis Susan B. , Dunbar W. Scott , MacGillivray Ross T.A.
Published: October 2012

Very large quantities of tailings are produced as a result of processing oil sands. After the sand particles settle out, a dense stable mixture of clay, silt, water with residual bitumen, salts, and organics called mature fine tailings (MFT) can remain in suspension for decades. Research into developing methods that would allow consolidation and sedimentation of the suspended particles is ongoing. We have studied the ability of a filamentous bacteriophage (called VP12 bearing the peptide DSQKTNPS at the N‐terminus of the major coat protein pVIII) to aggregate MFT. To understand the biophysical basis of the aggregation, phage‐induced aggregation of diluted MFT was measured at room temperature under varying conditions of pH, salt, detergent. Phage at concentrations of 5.0 × 1011/mL to 1012/mL induced rapid settling of the diluted MFT. The addition of sodium chloride (10 mM) lowered the concentration of phage required to induce aggregation. Since the non‐ionic detergents Triton‐X 100 and Tween‐20, and the ionic detergent sodium deoxycholate had little effect, hydrophobic interactions do not appear to be a major contributor to the phage‐induced aggregation of MFT. However, aggregation was prevented at pH values higher than 9.0 suggesting that positively charged amino acid residues are required for MFT aggregation by phage. Genetic engineering of the pVIII peptide sequence indicated that hydrogen bonding also contributes to phage‐induced aggregation. In addition, replacing the basic residue lysine with an alanine in the recombinant peptide of VP12 completely prevented phage‐induced aggregation. Three other phage displaying different amino acid sequences but all containing a lysine in the same position had variable aggregation efficiencies, ranging from no aggregation to rapid aggregation. We conclude that not only are the functional groups of the amino acids important, but the conformation that is adopted by the variable pVIII peptide is also important for phage‐induced MFT aggregation. Biotechnol. Bioeng. 2013; 110: 803–811. © 2012 Wiley Periodicals, Inc.
Application of high throughput pretreatment and co‐hydrolysis system to thermochemical pretreatment. Part 1: Dilute acid
Authors: Gao Xiadi , Kumar Rajeev , DeMartini Jaclyn D. , Li Hongjia , Wyman Charles E.
Published: October 2012

Because conventional approaches for evaluating sugar release from the coupled operations of pretreatment and enzymatic hydrolysis are extremely time and material intensive, high throughput (HT) pretreatment and enzymatic hydrolysis systems have become vital for screening large numbers of lignocellulosic biomass samples to identify feedstocks and/or processing conditions that significantly improve performance and lower costs. Because dilute acid pretreatment offers many important advantages in rendering biomass highly susceptible to subsequent enzymatic hydrolysis, a high throughput pretreatment and co‐hydrolysis (HTPH) approach was extended to employ dilute acid as a tool to screen for enhanced performance. First, a single‐step neutralization and buffering method was developed to allow effective enzymatic hydrolysis of the whole pretreated slurry. Switchgrass and poplar were then pretreated with 0.5% and 1% acid loadings at a 5% solids concentration, the resulting slurry conditioned with the buffering approach, and the entire mixture enzymatically hydrolyzed. The resulting sugar yields demonstrated that single‐step neutralizing and buffering was capable of adjusting the pH as needed for enzymatic saccharification, as well as overcoming enzyme inhibition by compounds released in pretreatment. In addition, the effects of pretreatment conditions and biomass types on susceptibility of pretreated substrates to enzymatic conversion were clearly discernible, demonstrating the method to be a useful extension of HTPH systems. Biotechnol. Bioeng. 2013; 110: 754–762. © 2012 Wiley Periodicals, Inc.
Evaluation of the feasibility of alcohols serving as external carbon sources for biological phosphorus removal induced by the oxic/extended‐idle regime
Authors: Wang Dongbo , Zheng Wei , Li Xiaoming , Yang Qi , Liao Dexiang , Zeng Guangming
Published: October 2012

Recently, a novel operational regime (i.e., the oxic/extended‐idle [OEI] regime) has been reported to successfully achieve enhanced biological phosphorus removal (EBPR) when employing glucose and volatile fatty acids as the sole substrate. In the OEI regime, polyphosphate accumulating organisms (PAOs) could get a selective advantage over other populations during the extended‐idle period where polyphosphate released but polyhydroxyalkanoates and glycogen transformations were negligible/low, thus energy requirements for maintenance purposes in the period could be covered by polyphosphate release. This study further evaluated the feasibility of alcohols as external carbon sources for EBPR induced by the OEI regime, as the available substrate in the raw wastewater is often deficient. First, phosphorus removal in the OEI process was compared, respectively, with methanol and ethanol as the sole substrate. The results showed that the ethanol‐reactor achieved 90.8 ± 2.3% of phosphorus removal, which was approximate twofold than the methanol‐reactor. Further studies displayed that the cells in the ethanol‐reactor contained more PAOs, and had higher activities of exopolyphosphatase and polyphosphate kinase than those in the methanol‐reactor. Also, the aerobic transformations of polyhydroxyalkanoates and glycogen in the ethanol‐reactor were, respectively, higher and lower than those in the methanol‐reactor, which were consistent with the reactors performances. Then, the feasibility of using ethanol as external substrate to enhance EBPR in the OEI process was confirmed for a municipal wastewater. Finally, EBPR performance and metabolic transformation values between the OEI and the anaerobic/oxic (A/O) regimes with ethanol as the sole substrate were compared. The results showed that EBPR in the ethanol‐OEI reactor was higher than that in the ethanol‐A/O reactor. All the above results proved that ethanol was a favorable external substrate to the OEI regime for EBPR enhancement. Biotechnol. Bioeng. 2013; 110: 827–837. © 2012 Wiley Periodicals, Inc.
Covalently grafted BMP‐7 peptide to reduce macrophage/monocyte activity: An in vitro study on cobalt chromium alloy
Authors: Tan Hark Chuan , Poh Chye Khoon , Cai Yanli , Soe Min Thun , Wang Wilson
Published: October 2012

Cobalt chromium (CoCr) alloy is widely used in orthopedic implants but its functional longevity is susceptible to inflammation related complications. Reduction of the development of chronic inflammation on the biomaterial surface would enhance direct bone‐implant bonding and improve implant survival and long‐term results. The BMP‐7 peptide was derived from the knuckle epitope of bone morphogenic protein‐7 (BMP‐7) and was conjugated via a cysteine amino acid at the N‐terminus. Mouse RAW 264.7 monocytes/macrophages were seeded on the CoCr substrates and inflammation was induced via lipopolysaccharide (LPS) challenge. The effects of BMP‐7 peptide on inflammation were evaluated by measuring the expression of inflammatory markers like toll‐like receptor‐4 (TLR‐4), tumor necrosis factor‐α (TNF‐α), and monocyte chemotactic protein‐1 (MCP‐1). ELISA and qPCR assays were used to study the inflammatory signals. BMP‐7 signaling pathway activation was shown by the presence of phosphorylation of Smad1/5/8. Utilizing the reactivity of polydopamine films to immobilize BMP‐7 peptide onto metal substrates may provide a promising approach for applications in situations where reduction of inflammation around implants would be beneficial in improving surgical outcome, bone healing, and implant integration. Biotechnol. Bioeng. 2013; 110: 969–979. © 2012 Wiley Periodicals, Inc.
Simulation of two dimensional electrophoresis and tandem mass spectrometry for teaching proteomics
Authors: Fisher Amanda , Sekera Emily , Payne Jill , Craig Paul
Published: October 2012

In proteomics, complex mixtures of proteins are separated (usually by chromatography or electrophoresis) and identified by mass spectrometry. We have created 2DE Tandem MS, a computer program designed for use in the biochemistry, proteomics, or bioinformatics classroom. It contains two simulations—2D electrophoresis and tandem mass spectrometry. The two simulations are integrated together and are designed to teach the concept of proteome analysis of prokaryotic and eukaryotic organisms. 2DE‐Tandem MS can be used as a freestanding simulation, or in conjunction with a wet lab, to introduce proteomics in the undergraduate classroom. 2DE Tandem MS is a free program available on Sourceforge at https://sourceforge.net/projects/jbf/. It was developed using Java Swing and functions in Mac OSX, Windows, and Linux, ensuring that every student sees a consistent and informative graphical user interface no matter the computer platform they choose. Java must be installed on the host computer to run 2DE Tandem MS. Example classroom exercises are provided in the Supporting Information. © 2012 by The International Union of Biochemistry and Molecular Biology
Clean, Convenient, High‐yield Access to Second‐generation Ru Metathesis Catalysts from Commercially Available Precursors
Authors: van Lierop Bianca J. , Reckling Amy M. , Lummiss Justin A. M. , Fogg Deryn E.
Published: October 2012

Expedient routes are described to the three dominant ruthenium catalysts currently used for olefin metathesis: the second‐generation Grubbs, Hoveyda, and indenylidene catalysts. Ligand exchange of the first‐generation PCy3 complexes with isolated free H2IMes, followed by treatment with a cation‐ exchange resin to remove the liberated phosphine, affords the clean targets in ≥95 % isolated yield from commercially available precursors, with no workup other than filtration and evaporation.
Crystal Growth Mechanisms and Morphological Control of the Prototypical Metal–Organic Framework MOF‐5 Revealed by Atomic Force Microscopy
Authors: Cubillas Pablo , Anderson Michael W. , Attfield Martin P.
Published: October 2012

Crystal growth of the metal–organic framework MOF‐5 was studied by atomic force microscopy (AFM) for the first time. Growth under low supersaturation conditions was found to occur by a two‐dimensional or spiral crystal growth mechanism. Observation of developing nuclei during the former reveals growth occurs through a process of nucleation and spreading of metastable and stable sub‐layers revealing that MOFs may be considered as dense phase structures in terms of crystal growth, even though they contain sub‐layers consisting of ordered framework and disordered non‐framework components. These results also support the notion this may be a general mechanism of surface crystal growth at low supersaturation applicable to crystalline nanoporous materials. The crystal growth mechanism at the atomistic level was also seen to vary as a function of the growth solution Zn/H2bdc ratio producing square terraces with steps parallel to the <100> direction or rhombus‐shaped terraces with steps parallel to the <110> direction when the Zn/H2bdc ratio was >1 or about 1, respectively. The change in relative growth rates can be explained in terms of changes in the solution species concentrations and their influence on growth at different terrace growth sites. These results were successfully applied to the growth of as‐synthesized cube‐shaped crystals to increase expression of the {111} faces and to grow octahedral crystals of suitable quality to image using AFM. This modulator‐free route to control the crystal morphology of MOF‐5 crystals should be applicable to a wide variety of MOFs to achieve the desired morphological control for performance enhancement in applications.
Intrinsically Sulfur‐ and Nitrogen‐Co‐doped Carbons from Thiazolium Salts
Authors: Paraknowitsch Jens Peter , Wienert Björn , Zhang Yuanjian , Thomas Arne
Published: October 2012

Carbon materials that are intrinsically co‐doped with nitrogen and sulfur heteroatoms are synthesised by facile annealing of nitrile‐functionalised thiazolium salts. Extremely high degrees of doping are achieved, especially for sulfur. The method further allows for direct tuning of the amounts of both N and S, establishing a new synthetic pathway in the emerging field of S‐doped carbon materials.
Vibrations‐Aided Gravitational Flow of Ultrafine Cohesive Limestone Powder – Measurements and Modeling
Authors: Kache Guido , Tomas Jürgen
Published: October 2012

Bei der Herstellung und Verarbeitung von ultrafeinen Pulvern sind eine zuverlässige Lagerung, Förderung und Dosierung unverzichtbar. Der Pulverfluss kann in einem Silo durch Brücken‐ oder Schachtbildung behindert werden. Zur Lösung dieses Fließproblems hat sich die Einleitung mechanischer Schwingungen mittels Schwingtrichter bewährt. Durch Schwingungsanregung während des Scherversuches werden die minimale Öffnungsweite zur Vermeidung von Brückenbildung und die Wandreibung deutlich vermindert. Anschließend werden diese Labor‐Auslegungsdaten an Versuchssilos überprüft. Dazu wird der Einfluss von Frequenz und Amplitude der Schwingungen auf den Pulverfluss untersucht.
Development of a Modeling Tool for the Systematic Design of Membrane Modules for Pervaporation
Authors: Schiffmann Patrick , Repke Jens‐Uwe
Published: October 2012

Die Bedeutung der Pervaporation (PV) in der chemischen Industrie wächst stetig und eine detaillierte sowie robuste Modellierung ist unabdingbar, um eine genaue Modul‐ und Anlagenauslegung durchzuführen. Im Rahmen eines Forschungsprojektes wird ein Membranmodul für die organophile PV konstruiert. Für eine industrielle Trennaufgabe werden organoselektive Membranen durch molekulare Oberflächenmodifikation hergestellt. Diese Arbeit befasst sich mit der Entwicklung einer dreistufigen Modellstruktur, die für die schrittweise Simulation von Membranmodulen verwendet wird. Die Simulationsergebnisse zeigen eine gute Übereinstimmung mit den experimentellen Daten aus der Pilotphase.
Influence of Rheology on the Flow Pattern in Stirred Biogas Plants
Authors: Brehmer Manuel , Eppinger Thomas , Kraume Matthias
Published: October 2012

Trotz des großen Anteils an den Stromgestehungskosten erfolgt die Auslegung der Rührtechnik in Biogasreaktoren nach wie vor empirisch. Im Rahmen dieses Artikels werden die Auswirkungen der Positionierung der Rührtechnik auf das Strömungsregime und folglich auf die Gasausbeute dargestellt. Dafür wird einleitend auf die Rheologie unterschiedlicher Gärgüter des Biogasprozesses eingegangen. Mit einem Rohrviskosimeter können für biogene Reststoffe, Klärschlamm und Maissilage exakte Messungen durchgeführt werden, die als Grundlage für die weiterführenden Strömungsuntersuchungen dienen. Diese zeigen, dass das durchmischte Volumen entscheidend von der Positionierung der hier betrachteten Tauchmotorrührwerke sowie der Substratzusammensetzung bzw. deren Rheologie abhängt.
Regional astrogliosis in the mouse hypothalamus in response to obesity
Authors: Buckman Laura B. , Thompson Misty M. , Moreno Heidi N. , Ellacott Kate L.J.
Published: October 2012

Obesity is associated with chronic low‐grade inflammation in peripheral tissues, which contributes to the development of comorbidities such as insulin resistance and cardiovascular disease. While less extensively characterized, obesity also promotes inflammation in the central nervous system (CNS) and the consequences of this inflammation for CNS function are only beginning to be examined. In response to CNS insults such as inflammation, astrocytes undergo a process of hypertrophy and hyperplasia known as reactive astrogliosis. We used immunohistochemistry to examine the differential distribution of the astrocyte marker glial‐fibrillary acidic protein (GFAP) in the brains of diet‐induced or genetically obese mice compared with their respective lean controls to determine whether different nuclei of the hypothalamus showed comparable astrogliosis in response to obesity. The areas that showed the highest differential GFAP immunoreactivity between lean and obese animals include the medial preoptic, paraventricular, and dorsomedial nuclei. Comparatively, little astrogliosis was seen in the ventromedial nucleus, lateral hypothalamus, or anterior hypothalamic area. In obese animals high levels of GFAP immunoreactivity were often associated with the microvasculature. There were no differences in the differential distribution of GFAP staining between obese animals and their lean controls in the diet‐induced compared with the genetic model of obesity. The exact cause(s) of the astrogliosis in obesity is not known. The finding that obesity causes a distinct pattern of elevated GFAP immunoreactivity associated with microvessels suggests that the astrogliosis may be occurring as a response to changes at the blood–brain barrier and/or in the peripheral circulation. J. Comp. Neurol., 521:1322–1333, 2013. © 2012 Wiley Periodicals, Inc.