bluuebunny/crossref_metadata_2025 huggingface dataset:
Cytotoxicity of anticancer aziridinyl-substituted benzoquinones in primary mice splenocytes.
Authors: Miliukienė Valė , Nivinskas Henrikas , Čėnas Narimantas
Published: February 2019

The anticancer activity of aziridinyl-quinones is mainly attributed to their
quinone oxidoreductase 1 (NQO1)-catalyzed two-electron reduction into DNA-alkylating products. However, little is known about their cytotoxicity in primary cells, which may be important in understanding their side effects. We found that the cytotoxicity of aziridinyl-unsubstituted quinones (n = 12) in mice splenocytes with a low amount of NQO1, 4 nmol × mg(-1) × min(-1), was caused mainly by the oxidative stress. Aziridinyl-benzoquinones (n = 6) including a novel anticancer agent RH1 were more cytotoxic than aziridinyl-unsubstituted ones with the similar redox properties, and their cytotoxicity was not decreased by an inhibitor of NQO1, dicumarol. The possible reasons for their enhanced cytotoxicity are discussed.
Structural biology of the influenza virus fusion peptide.
Authors: Worch Remigiusz
Published: February 2019

The release of influenza RNA inside the host cell occurs through the fusion of two membranes, the viral envelope and that of the cellular endosome. The fusion is mediated by the influenza hemagglutinin protein (HA), in particular by the fusion peptide (HAfp) located in the N-terminal fragment of HA2 subunit. This protein fragment anchors in the internal endosomal membrane, whereas the C-terminal HA2 part comprises a transmembrane domain (TMD) embedded in the viral envelope. A drop of pH in the endosome acts as the main trigger for HA2 large conformational change that leads to anchoring of the fusion peptide, close contact of the membranes and the subsequent fusion. Throughout the years the major research effort was focused on a 20-amino acid fragment (HAfp1-20), shown by NMR to adopt a 'boomerang'-like structure. However, recent studies showed that extending HAfp1-20 by three highly conserved residues W21-Y22-G23 leads to formation of a unique, tight helical hairpin structure. This review summarizes recently discovered structural aspects of influenza fusion peptides and their relations with the membrane fusion mechanism.
Vaccination against influenza in pregnant women.
Authors: Brydak Lidia Bernadeta , Nitsch-Osuch Aneta
Published: February 2019

Pregnancy places otherwise healthy women at an increased risk of complications arising from an influenza infection. It is suggested that physiological changes such as immunological changes, increased cardiac output and oxygen consumption, as well as lung tidal volume might increase the susceptibility to influenza complications if infection occurs during pregnancy. Immunization of pregnant women against influenza is currently recommended in many countries and has been proven to be safe and effective in reducing rates and severity of the disease in vaccinated mothers and their children. Influenza vaccination is also cost-effective. Nevertheless, influenza vaccine coverage remains low in pregnant women. This might stem from the lack of healthcare workers' education, a feeling among the general public that influenza is not a serious disease and a failure of prenatal care providers to offer the vaccine. In order to protect pregnant women and infants from influenza related morbidity and mortality an educational programme targeting healthcare workers in charge of pregnant women should be implemented.
Graves' disease, Celiac disease and liver function abnormalities in a patient--clinical manifestation and diagnostic difficulties.
Authors: Góra-Gębka Magdalena , Woźniak Małgorzata , Cielecka-Kuszyk Joanna , Korpal-Szczyrska Maria , Sznurkowska Katarzyna , Zagierski Maciej , Jankowska Irena , Plata-Nazar Katarzyna , Kamińska Barbara , Liberek Anna
Published: February 2019

Autoimmune diseases due to probable common pathogenesis tend to coexist in some patients. Complex clinical presentation with diverse timing of particular symptoms and sophisticated treatment with numerous side effects, may cause diagnostic difficulties, especially in children. The paper presents diagnostic difficulties and pitfalls in a child with Graves' disease, celiac disease and liver function abnormalities.
A proteomics approach to identify the differential protein level in cardiac muscle of diabetic rat.
Authors: Karthik Dhanaraj , Vijayakumar Ravichandran , Pazhanichamy Kalailingam , Ravikumar Sivanesan
Published: February 2019

Cardiovascular proteomics investigation reveals the characterization and elucidation of the novel therapeutic targets and strategies to prevent the development of heart failure associated diabetic complication by using 2DE and MS.
The experimental animals were made diabetic with a single intraperitoneal injection of alloxan (150 mg/kg of bw). Albino rats were randomly divided into four individual groups: Group-I control (n=6), group-II alloxan-induced diabetic rats, untreated (n=6), group-III (n=6) and group-IV (n=6) alloxan-induced diabetic rats were treated with aqueous and ethanolic extracts of Cynodon dactylon for 15 days, respectively. Animals were euthanized to collect the heart tissues and blood samples. 2DE sample preparation, gel running and staining (n=6: each groups) were performed at the same time to avoid variation. The result of six gel images from each group were analyzed and evaluated as one match set with 2D software (P
Investigation of asparagine deamidation in a SOD1-based biosynthetic human insulin precursor by MALDI-TOF mass spectrometry.
Authors: Bierczyńska-Krzysik Anna , Łopaciuk Małgorzata , Pawlak-Morka Renata , Stadnik Dorota
Published: February 2019

A biosynthetic human insulin precursor displayed enhanced susceptibility to deamidation at one particular site. The present study was undertaken to monitor progress of precursor deamidation at successive manufacturing stages. MALDI-TOF/TOF MS in combination with controlled endoproteinase Glu-C and endoproteinase Asp-N proteolysis was used for rapid and unambiguous determination of deamidated residue within the investigated structure. Close inspection of isotopic distribution patterns of peptides resulting from enzymatic digestion enabled determination of distinct precursor forms occurring during the production process. Asn, Asp, isoAsp and succinimide derivatives of the amino acid at position 26 were unambiguously identified. These modifications are related to the leader peptide of a precursor encompassing amino acid sequence corresponding to that of superoxide dismutase [Cu-Zn] (SOD1 1, EC=1.15.1.1). Monitoring of precursor deamidation process at successive manufacturing stages revealed that the protein folding stage was sufficient for a prominent replacement of asparagine by aspartic and isoaspartic acid and the deamidated human insulin precursor constituted the main manufactured product. Conversion proceeded through a succinimide intermediate. Significant deamidation is associated with the presence of SNG motif and confirms results achieved previously on model peptides. Our findings highlight an essential role of the specific amino acid sequence on accelerated rate of protein deamidation. To our knowledge, this is the first time that such a dramatic change in the relative abundance of Asp and isoAsp resulting from protein deamidation process is reported.
Determination of lysosomal exoglycosidases in human saliva.
Authors: Chojnowska Sylwia , Zalewska Anna , Knaś Małgorzata , Waszkiewicz Napoleon , Waszkiel Danuta , Kossakowska Agnieszka , Zwierz Krzysztof
Published: February 2019

Currently we observe a growing interest in human saliva as a non-invasive material for diagnosis and monitoring of general and oral diseases.
The aim of our study was adaptation of the Marciniak et al. (Marciniak J, Zalewska A, Popko J, Zwierz K, 2006, Clin Chem Lab Med 44: 933-937) method for determination of HEX and GLU activity in synovial fluid, and for determination of: HEX and GLU, as well as MAN, GAL, and FUC activity in human saliva.
Under optimal conditions, 10 μl of saliva for HEX, and 30 μl for GLU, MAN, GAL and FUC, were sufficient for determination of human salivary exoglycosidases activity with variation coefficient ranging from 0.89 for GLU to 0.99 for GAL.
The adapted method for exoglycosidases activity determination in human saliva is sufficiently sensitive and precise to use in clinical diagnosis.
O direito à identidade pessoal no Brasil
Authors: Bolesina Iuri , Gervasoni Tamiris Alessandra
Published: February 2019

Com a repersonalização do direito civil, motivada pela constitucionalização do Direito, os direitos da personalidade ganharam espaço destacado no âmbito direito privado. Em face disso, o problema a ser investigado neste estudo é: perpassando pelas críticas lançadas, qual o fundamento do direito à identidade e quais os seus contornos jurídicos na atualidade? Como metodologia utiliza-se a abordagem dedutiva e o procedimento monográfico. A técnica de pesquisa é a documentação indireta por meio da revisão bibliográfica. Para tanto, o caminho de desenvolvimento traçado será: no primeiro capítulo analisar-se-á a matriz do direito à identidade que é a relação dialogal entre igualdade e diferença. Na segunda parte, o objeto de estudo será o direito à identidade em si, buscando perceber sua origem e desenvolvimento no ocidente. Por fim, no terceiro item, a pesquisa mirará observar a posição jurídica do direito à identidade no Brasil, apontando suas potencialidades e insuficiências enquanto direito da personalidade autônomo. Em face do exposto, demonstra-se que o direito à identidade aparece como o direito que permite a uma pessoa ser “quem” ela é e “como” ela é, protegendo, respeitando e concretizando seu projeto existencial no presente e no futuro. Logo, o direito à identidade aparece como um direito fundamental, vinculado aos direitos da personalidade, que concretiza não apenas a dignidade da pessoa humana, mas também o princípio do livre desenvolvimento da personalidade.
Anesthetic Challenges for Modified Bentall Procedure in a Pregnant Marfan Patient with Acute Stanford Type A Dissection
Authors: Tantri Irma , Menor Theresa , Laborte Nelia
Published: February 2019

Aortic dissection is a life-threatening condition which requires immediate surgical intervention. It has been estimated that half of aortic dissection and/or ruptures in women younger than 40 years of age have been associated with pregnancy.19 The limited data on the coincidence of Marfan syndrome, pregnancy and aortic dissection makes its anesthetic management a formidable challenge to any anesthesiologist.

This is a case of a 33-year-old G1P0, 28 weeks age of gestation with Marfan syndrome, who had Aortic Dissection Stanford type A and underwent an emergency Modified Bentall’s surgery with cardiopulmonary bypass and deep hypothermic circulatory arrest.

This case illustrates the dilemma of managing this case since there are two patients involved, mother and fetus. Wrong decision could result in demise of both. Although the aim is life for both, survival of one without neurologic sequelae is already considered a success.
“I’m Thinking I Want to Live a Better Life”: Syrian Refugee Student Adjustment in New Brunswick
Authors: Massfeller Helen , Hamm Lyle Donald
Published: February 2019

In this paper, the authors explore the re-adjustment experiences of seven refugee students from Syria and Iraq who enrolled in a large high school in New Brunswick. Data were collected through semi-structured interviews, school and community documents, and field notes. Five themes were identified and are reported and discussed in this paper. Recommendations for future direction regarding how to successfully integrate Syrian refugee children into Canadian schools are provided.
PREVALENCE OF TRICHOMONIASIS IN ASYMPTOMATIC PREGNANT WOMEN POPULATION IN BANDUNG, WEST JAVA, INDONESIA
Authors: Achdiat Pati Aji , Dwiyana Reiva Farah , Feriza Vina , Rowawi Rasmia , Effendi Rendy Ariezal , Suwarsa Oki , Gunawan Hendra
Published: February 2019

About 81% of pregnant women with trichomoniasis are asymptomatic, while trichomoniasis in pregnant women can increase the risk of complications, include premature rupture of membranes, preterm birth, and babies with low birth weight. Trichomoniasis can also increase the risk of other sexually transmitted infections (STIs) and human immunodeficiency virus (HIV) transmission. Trichomoniasis case in pregnant women could be influenced by demographic characteristics,, the sexual behavior, and also the diagnostic method used. Until now, there is no data about prevalence of trichomoniasis in pregnant women in Indonesia. The aim of this research was to determine the prevalence of trichomoniasis in pregnant women in Bandung, West Java, Indonesia. A descriptive cross-sectional study was performed in December 2016 until January 2017. The study participants were 50 pregnant women who visit antenatal care to Obstetric and Gynecology Clinic of ’Rumah Sakit Khusus Ibu dan Anak Kota Bandung’, and meet the inclusion and exclusion criteria, through consecutive sampling. The study participants had a history taking, venereological examination, and Trichomonas rapid test from vaginal swabs. Trichomoniasis in this study was diagnosed based on Trichomonas rapid test, a test that uses color immunochromatographic, capillary flow, dipstick technology, and has high sensitivity and specificity in diagnosing trichomoniasis. Almost all participants in this study were low risk pregnant women to have STI based on demographic characteristics and sexual behaviour. The positive Trichomonas rapid test result was found from one of 50 study participants. In conclusion, prevalence of trichomoniasis in pregnant women in Bandung was 2%. Trichomoniasis case in low-risk pregnant women population is still found.
Realization of Maxwell’s Hypothesis: A Heat-Electric Conversion in Contradiction to the Kelvin Statement
Authors: Fu Xinyong , Fu Zitao
Published: February 2019

In a vacuum tube, two identical and parallel Ag-O-Cs surfaces, A and B, with a work function 0.8eV, ceaselessly emit thermal electrons at room temperature. The thermal electrons are controlled by a static uniform magnetic field (a magnetic demon), and the number of electrons migrate from A to B exceeds the one from B to A (or vice versa). The net migration from A to B quickly results in a charge distribution, with A charged positively and B negatively. A potential difference between A and B emerges, and the tube outputs an electric current and a power to a load (a resistance, e.g.). The ambient air is a single heat reservoir in the experiment, and all the heat extracted by the tube from the air is converted into electric energy without producing other effects. We believe the experiment is in contradiction to the Kelvin statement of the second law.
Identification of Critical Source Areas (CSAs) and Evaluation of Best Management Practices (BMPs) in Controlling Eutrophication in the Dez River Basin
Authors: Babaei Hadi , Nazari-Sharabian Mohammad , Karakouzian Moses , Ahmad Sajjad
Published: February 2019

Best Management Practices (BMPs) are commonly used to control pollution in the river basins. Prioritization of BMPs helps improve the efficiency and effectiveness of pollution reduction, especially in Critical Source Areas (CSAs) that produce the highest pollution loads. Recently, the Dez River in Khuzestan, Iran, has become highly eutrophic from the overuse of fertilizers and pesticides. In this basin, dry and irrigated farming produce 77.34% and 6.3% of the Total Nitrogen (TN) load, and 83.56% and 4.3% of the Total Phosphorus (TP) load, respectively. In addition, residential, pasture, and forest land uses together account for 16.36% of the TN and 12.14% of the TP load in this area. The Soil and Water Assessment Tool (SWAT) was implemented to model the Dez River basin and evaluate the applicability of several BMPs, including point source elimination, filter strips, livestock grazing, and river channel management, in reducing the entry of pollution loads to the river. Sensitivity analysis and calibration/validation of the model was performed using the SUFI-2 algorithm in the SWAT Calibration Uncertainties Program (SWAT-CUP). The CSAs were identified using individual (sediment, TN, TP) and combined indices, based on the amount of pollution produced. Among the BMPs implemented, the 10 m filter strip was most effective in reducing TN load (42.61%), and TP load (39.57%).
Modelling Recovery Rates for Non-performing Loans
Authors: Bellotti Anthony , Ye Hui
Published: February 2019

Based on a rich data set of recoveries donated by a debt collection business, recovery rates for non-performing loans taken from a single European country are modelled using linear regression, linear regression with Lasso, beta regression and inflated beta regression. We also propose a two-stage model: beta mixture model combined with a logistic regression model. The proposed model allows us to model the multimodal distribution we find for these recovery rates. All models are built using loan characteristics, default data and collections data prior to purchase by the debt collection business. The intended use of the models is to estimate future recovery rates for improved risk assessment, capital requirement calculations and bad debt management. They are compared using a range of quantitative performance measures under K-fold cross validation. Among all the models, we find that the proposed two-stage beta mixture model performs best.
Did You Send It? Enhancing the Use of E-Mail in Scientific Research and in the Academy
Authors: Pagliaro Mario
Published: February 2019

Misuse of the main information technology used in the academy, electronic mail, can be ended through expanded knowledge and renewed education. Becoming acquainted with advanced time management and communication pragmatics students will shortly remedy today’s e-mail misuse leading to professors overwhelmed by anxiety-driven e-mails; and scholars wasting valued time on e-mail minutia. Universities reformed by managers literate in today’s management theory will focus again on teaching and research, prioritizing scholarly deep work and thus abandoning the use of “urgent” e-mails with the request of spreadsheets and reports. Professors across the world need to educate undergraduate students on the healthy and productive utilization of the e-mail.
Increase in Mutual Information During Interaction of the Brain with Environment Contributes to Perception
Authors: Gupta Daya , Bahmer Andreas
Published: February 2019

Perception and motor interaction with physical surroundings can be analyzed by the changes in probability laws governing two possible outcomes of neuronal activity, namely the presence or absence of spikes (binary states). Perception and motor interaction with physical environment are accounted partly by the reduction in entropy within the probability distributions of binary states of neurons in distributed neural circuits, given the knowledge about the characteristics of stimuli in physical surroundings. This reduction in the total entropy of multiple pairs of circuits in networks, by an amount equal to the increase of mutual information among them, occurs as sensory information is processed successively from lower to higher cortical areas or between different areas at the same hierarchical level but belonging to different networks. The increase in mutual information is partly accounted by temporal coupling as well as synaptic connections as proposed by Bahmer and Gupta [1]. We propose that robust increases in mutual information, measuring the association between the characteristics of sensory inputs and neural circuits connectivity patterns, are partly responsible for perception and successful motor interactions with physical surroundings. It is also argued that perception from a sensory input is the result of networking of many circuits to a common circuit that primarily processes the given sensory input.
Recent Developments in Solar Energy-Harvesting Technologies for Building Integration and Distributed Energy Generation
Authors: Vasiliev Mikhail , Nur-E-Alam Mohammad , Alameh Kamal
Published: February 2019

We present a review of the current state of the field for a rapidly evolving group of technologies related to solar energy harvesting in built environments. In particular, we focus on recent achievements in enabling the widespread distributed generation of electric energy assisted by energy capture in semi-transparent or even optically clear glazing systems and building wall areas. Whilst concentrating on the cutting-edge recent results achieved in the integration of traditional photovoltaic device types into novel concentrator-type windows and glazings, we compare the main performance characteristics reported with these achievable using more conventional (opaque or semi-transparent) solar cell technologies. A critical overview of the current status and future application potential of multiple existing and emergent energy harvesting technologies for building integration is provided.
Analisis Model Mental Siswa pada Materi Hidrolisis Garam di Klaten
Authors: Andina Rahma Esi , Ridwan Achmad , Rahmawati Yuli
Published: February 2019

Penelitian ini bertujuan untuk menganalisis model mental siswa dalam materi hidrolisis garam. Subjek penelitian adalah siswa kelas XI jurusan IPA yang merupakan kelas unggulan di Klaten. Penelitian ini merupakan penelitian kualitatif dengan metode yang digunakan yaitu etnografi. Teknik pengumpulan data dilakukan dengan observasi kelas, wawancara mendalam, dan reflektif jurnal siswa. Hasil penelitian menunjukkan bahwa siswa membangun model mental berdasarkan pemahaman dan pengalaman siswa yang dipengaruhi oleh lingkungan sekitar siswa serta karakteristik siswa, yaitu sopan santun, empati komunikasi, dan menganggap bahwa guru selalu benar. Analogi yang digunakan siswa dalam membangun pemahaman mengenai materi hidrolisis garam berasal dari budaya dan lingkungan sekitar siswa, yaitu ikan, budaya padusan, dan kegiatan menenun. Model mental siswa pada materi hidrolisis garam terbagi dalam model mental yang sesuai dan model mental yang tidak sesuai pada konsep hidrolisis garam dan proses reaksi hidrolisis, garam yang mengalami hidrolisis, dan sifat garam yang mengalami hidrolisis. Pemahaman guru terhadap model mental siswa akan membantu guru dalam menciptakan pembelajaran yang bermakna.

Kata Kunci: Model Mental, Etnografi, Hidrolisis Garam
Integrasi CoRe Framework dan Strategi Metakognitif dalam Pengembangan Pedagogy Content Knowledge Calon Guru Kimia pada Pembelajaran Telaah Kurikulum Kimia
Authors: Fitriani Ella , Rahmawati Yuli , Nurbaity Nurbaity , Muhab Sukro
Published: February 2019

Penelitian ini terfokus pada analisis Pedagogical Content Knowledge (PCK) calon guru kimia menggunakan CoRe (Content Representation) Framework dan strategi metakognitif  pada mata kuliah Telaah Kurikulum Kimia.  PCK merupakan representasi gabungan antara isi materi pelajaran dan pedagogik yang dimilik oleh guru sehingga siswa tertarik dan mudah untuk memahami suatu materi (Shulman, 1987). Oleh karena itu, CoRe framework dan strategi metakognitif pada penelitian ini digunakan untuk mengembangkan penguasaan konsep kimia dan cara menyampaikan konsep tersebut. Penelitian ini menggunakan pendekatan kualitatif, dengan studi interpretif kualitatif hingga menghasilkan profil PCK calon-calon guru kimia terkait dengan penguasaan konsep-konsep kimia. Data diperoleh dari rubrik PCK, MAIT (Metacogitive Awareness Inventory for Teachers), wawancara, observasi, nilai tes konsep, dan kertas refleksi. Hasil penelitian ini menunjukkan bahwa tingkat PCK calon-calon guru kimia tergolong tinggi. Terlihat bahwa Content Knowledge (CK) yang mereka miliki sedikit lebih tinggi daripada Pedagogical Knowledge (PK). Hasil MAIT (Metacogitive Awareness Inventory for Teachers) juga menunjukkan bahwa calon-calon guru tersebut memiliki kesadaran metakognitif yang sangat tinggi sehingga mereka mengetahui kelemahan dan kekuatannya sendiri dalam mengajar.

 

Kata kunci: Pedagogical Content Knowledge, Content Representation, Strategi Metakognitif, Telaah Kurikulum Kimia
Penerapan Model Problem Based Learning (PBL) Berbasis Pendekatan Saintifik untuk Meningkatkan Penguasaan Konsep pada Materi Pokok Kelarutan dan Hasil Kali Kelarutan
Authors: Rafiuddin R , Dali Arniah , Anton La Ode Rusdi
Published: February 2019

Telah dilakukan penelitian yang bertujuan untuk mengetahui keefektifan penerapan model problem based learning berbasis pendekatan saintifik terhadap penguasaan konsep. Desain penelitian menggunakan  pretest-posttest  control  group  design.  Populasi  penelitian  ini  terbagi  atas  dua  kelas paralel  sebanyak  58  siswa.  Teknik  pengambilan  sampel  menggunakan  teknik  purposive  sampling. Sampel penelitian ini yaitu kelas XI-IPA4  sebagai kelas eksperimen sebanyak 29 siswa dan kelas XI- IPA1   sebagai kelas kontrol sebanyak 29 siswa. Instrumen penelitian untuk menentukan karakteristik konsep menggunakan format analisis konsep dan format peta konsep. Profil penguasaan konsep menggunakan butir tes pilihan ganda beralasan sebanyak 10 nomor. Peningkatan penguasaan konsep menggunakan  rumus  N-gain.  Efektivitas  pembelajaran  menggunakan  rumus  uji  beda  (t).  Serta tanggapan siswa menggunakan angket. Berdasarkan hasil analisis ditemukan data: (1) Terdapat 14 label  konsep  pada  materi  pokok  Kelarutan  dan  Hasil  Kali  Kelarutan,  terdiri  dari  28%  konsep menyatakan prinsip abstrak meliputi: Kesetimbangan Kelarutan, Hasil Kali Ion Kesetimbangan (Ksp), Hasil Kali Ion (Qsp), dan Elektrolit Sukar Larut, terdapat 14,29% konsep yang menyatakan ukuran atribut meliputi: Suhu dan Derajat Keasaman (pH), Serta terdapat 57,14% konsep yang menyatakan proses meliputi: Kelarutan, Ion Senama, Pengendapan, Larutan Elektrolit, Elektrolit Biner, Elektrolit Terner, Elektrolit Kuarterner, Larutan Jenuh; (2) Diperoleh perbandingan rerata skor post-test tertinggi dan terendah penguasaan konsep siswa kelas eksperimen dan kelas kontrol. Perbandingan untuk skor post-test tertinggi yaitu 97,04>94,58 pada label konsep Larutan Jenuh, sedangkan perbandingan skor post-test terendah kelas eksperimen yaitu 72,70 pada label konsep Elektrolit Terner dan 70,43% pada kelas kontrol; (3) Indeks N-gain kelas eksperimen sebesar 0,77 berkategori tinggi dibandingkan kelas kontrol sebesar 0,70 berkategori sedang; (4) Penerapan model problem based learning berbasis pendekatan saintifik pada kelas eksperimen efektif meningkatkan penguasaan konsep siswa dengan post-test dan N-gain sig. (2-tailed) < 0,05, selanjutnya efektif untuk diterapkan pada kelompok siswa berkemampuan tinggi dan sedang; (5) Penerapan model problem based learning berbasis pendekatan saintifik memiliki tanggapan baik dengan persentase 75,16%.

Kata kunci

Model Problem Based Learning, Pendekatan Saintifik, Penguasaan Konsep, Kelarutan dan Hasil Kali Kelarutan
A correção de erros e as relações entre avaliação por pares e autoavaliação no ambiente teletandem
Authors: Cavalari Suzi Marques Spatti , Freschi Ana Carolina
Published: February 2019

Este trabalho tem por objetivo investigar a correção de erros no contexto teletandem, evidenciando os momentos em que ambos os parceiros se envolvem. O teletandem é uma forma de telecolaboração em que pares de aprendizes de línguas-culturas diferentes interagem virtualmente a fim de aprenderem um com o outro por meio de recursos de texto, áudio e vídeo. Trata-se de um estudo de base qualitativa e interpretativista que utiliza como dados gravações de sessões orais de teletandem. Os participantes são três pares de aprendizes que interagem em português e em inglês. Neste estudo, enfocamos os dados em língua portuguesa e a análise revela que a avaliação por pares envolve não apenas a avaliação do parceiro linguisticamente mais competente, mas, principalmente, a avaliação do próprio aprendiz (autoavaliação) a respeito do que é considerado certo ou errado em sua produção ou compreensão em língua estrangeira.
Automatic Identification of Procedural Adherence in Well Construction-Operations
Authors: V Sai , Chambon Sylvain , Erge Oney , Mansour Darine , Hamzah Mohammad
Published: February 2019

The following paper describes a system that facilitates the creation of a machine-understandable representation of well construction operating procedures, and a runtime component which automatically identifies, from sensor data, the degree of compliance to those operating procedures. The procedures define a sequence of operations and operating limits that should be adhered to for an operation time interval.

The constructed system automates the processing of sensor, data and facilitates an analysis of the level of adherence to operating procedures during the well construction process. It also illuminates when and where deviations from the intended or expected processes occur.
Deep Learning Model for Classifying Cutting Volume at Shale Shakers in Real-Time via Video Streaming
Authors: Du Xunsheng , Jin Yuchen , Wu Xuqing , Liu Yu , Wu Xianping , Awan Omar , Roth Joey , See Kwee Choong , Tognini Nicolas , Chen Jiefu , Han Zhu
Published: February 2019

A real-time deep learning model is proposed to analyze the volume of cuttings from a shaker on an offshore drilling rig. The model is able to extract features and perform real-time classification in relatively good accuracy compared to the traditional video analytics method, which consumes enormous time on the feature extraction. Our approach mainly consists of two parts: 1) a multi-thread engine for decoding, processing, and encoding real-time video streams. The video streaming is offered by a modularized service called RSVP (Rig-Site Virtual Presence). RSVP enables aggregating, storing, transrating/transcoding, streaming, and visualization of video data from the rig. 2) a convolutional neural network (CNN) for the quantitative analysis. The CNN is pre-trained with videos collected from previous drilling operations. Additional noises are added to the video during the training stage to improve the robustness of the model. Each video frame needs to be properly normalized and re-scaled to a fixed size before fed into the CNN. The CNN will generate output to classify the volume of cuttings in real-time. The classification result includes category labels, ("ExtraHeavy", "Heavy", "Light", and "None"), as well as the probability for each label. The model and the workflow have been tested on videos streamed directed from an offshore drilling rig. The video stream has a bitrate of 137Kbps, 5.84 frames/s, and a frame size of 720x486. The CNN is trained with an Nvidia GeForce 1070 GPU. The deep learning model and the workflow is tested on a machine without GPU support. Due to the implementation of the multi-threaded video processing engine, we can handle decoding, encoding, video preprocessing and classification in real-time. This allows us to receive a real-time video stream and display the classification results with encoded frames on the user-side screen at the same time. In order to evaluate the result, we build the confusion matrix to facilitate the visualization of the performance of the model. Compared to results manually labeled by engineers, our model achieves more consistent results with improved confidence. The novelty of the project is the capability of monitoring and classifying the cutting volume at shale shakers in real-time via the video streaming.
Monte Carlo Analysis of Advanced Spline Curves for Wellbore Trajectory Uncertainty Calculations
Authors: McKenna Kirtland , Eustes Alfred , Abughaban Mahmoud , Shahri Mojtaba
Published: February 2019

The wellbore position uncertainty model is an important part of well design and operational considerations particularly for multi-well pads. The true uncertainty ellipsoids are dependent on the wellbore trajectory calculation method as much as it is on the quality of the survey measurements. Using the advanced spline curve method, more accurate uncertainty ellipsoids can be generated enabling engineers to optimize wellbore position for drilling, geological, reservoir, and production engineering applications.

To demonstrate that the advanced spline curve method models the true wellbore position more accurately than minimum curvature, trajectory calculations of a well surveyed with high resolution continuous gyroscope measurements are compared with the same wellbore after down sampling. The error of the two methods with the down sampled survey are compared to the base case. With the advanced spline curve method established, the uncertainty ellipsoid is calculated for each survey station for a set of wells on a multi-well pad. A Monte Carlo simulation using an industry standard error model for the survey measurements generated the uncertainty ellipsoids. The confidence interval, agreement of distribution, and collision risk of both calculation methods are evaluated and compared to a high-resolution survey.

This paper presents a Monte Carlo analysis of the wellbore position error model generated by the advanced spline curve method to that of the error model generated by the minimum curvature method. The error induced by the calculation method is reduced loosening the constraint of collision risk on wellbore design. Improved knowledge of the wellbore position benefits all engineering aspects for the life of the well.
Performance Impact of Downhole Data from Wired Drill Pipe and Downhole Sensors
Authors: Giltner Molly , Earle Linsay , Willis John , Tellez Diego , Neel Randall
Published: February 2019

High-frequency real-time drilling data from wired drill pipe has provided new insights on bottomhole assembly (BHA) dynamics in the New Mexico Delaware Basin. An enhanced understanding of downhole dynamics, formation characteristics, and their impact on bit and tool life has enabled the operator to optimize performance and achieve further improvements. Through these efforts, drilling time in a particular hole section has been reduced by 25%. The timesavings, combined with a reduction in trips and tool damage, has resulted in a 33% reduction in cost per foot.

The real-time downhole data provided increased understanding of the occurrence and mitigation of common drilling dysfunctions such as torsional vibration, whirl, axial vibration, motor micro-stalls, and pipe buckling. Both the data explaining downhole performance and the successful practices that resulted from analysis of the downhole data are discussed in this paper. The data and results included in this paper contribute to the improved performance of the industry in this area of high activity and are useful for other areas with similar drilling practices.
The Mechanical Response of Concentric Cemented Casings Exposed to Arbitrary Transverse External Geomechanical and Salt Loads
Authors: Sathuvalli Udaya B , Krishna Shree , Suryanarayana P V
Published: February 2019

When wellbores are exposed to loads of geomechanical origin, the outer casings can become vulnerable to the transverse load components. These loads are usually non-uniform in character (Veeken et al. 1994). The collapse resistance of tubulars to non-uniform loads is substantially lower than their resistance to uniform loads. In the face of such reduced tubular strength, the well engineer uses thick walled high strength casings or a system of concentric cemented casings (Clegg 1971; Pattillo and Rankin 1981; Pattillo et al. 1995). In either case, the designer has to determine a quantitative measure of well integrity i.e., a safety factor (SF) of the casing for the non-uniform loading. In our industry, well designers have used finite element analyses (FEA) to assess the mechanical response of the casings subjected to such loads (Pattillo et al. 1995; Li et al. 2003).

The simplest stress analysis problem in such situations consists of at least three cylinders, the innermost casing, the cement sheath and the formation up to the farfield boundary. Depending on the numerical methods employed in the geomechanical analysis, the farfield geomechanical loads are presented as displacements or tractions. In this paper, we present an analytical procedure to determine the mechanical response of a system of nested concentric cylinders exposed to an arbitrary traction or displacement on the outer radius of the outermost cylinder. We use the solution to quantify the effect of the loads on the concentric casings and the intervening cement sheaths, and to assess the effect of the formation. To this end we use well-known methods employed in the theory of elasticity to derive our solution. The analytical solution presented in the mathematical appendices can be implemented in a programmable spreadsheet.
A Novel Mechanical Tool for Annular Cement Verification
Authors: De Andrade Jesus , Fagerås Sondre , Sangesland Sigbjørn
Published: February 2019

The annular casing cement is an important part of the well barrier throughout the life cycle of a well. With the increasing number of subsea plug and abandonment (P&A) operations, increased attention is now given to annular cement evaluation and the ability to prove adequate zonal isolation. Today, cement evaluation by logging is performed almost exclusively using acoustic logging tools. One of the concerns when it comes to cement integrity is the frequently occurring micro-annulus at the casing-cement interface. Yet, a typical cement evaluation tool may lack of accuracy on its evaluation. Hence, a novel concept for the evaluation of casing-cement micro-annulus has been proposed.

This paper describes a mechanical-based approach for cement evaluation – the Annulus Verification Tool (AVT). The AVT applies a radial force on the casing inner wall that yields an ovalization of the cross-section, while recording the radial displacement of the casing. A prototype of the AVT has been constructed along with an experimental setup to allow for initial testing of the tool. This comprises the construction of full-scale diameter samples representing a typical 9 5/8-in. production casing cement job, with the possibility to generate a uniform micro-annulus of a known size at the casing-cement interface.

The tests performed have shown that the AVT is able to differentiate a casing supported by an annular cement sheath from a free pipe, due to the stiffness contrast. By measuring the casing radial displacement with high resolution, the results have shown that a microannulus can be detected and its size quantified with good accuracy. Experimental tests performed with tool eccentricity and tilting has shown that the AVT should be kept centralized to achieve accurate quantification of the microannulus size.

The AVT module is meant to complement the acoustic tool sting used today, and to improve evaluation of the cement sheath's sealing capability, especially in cases where a micro-annulus is detected or suspected. If an existing microannulus is suspected, the AVT logging response may confirm its occurrence, quantify its size and aid the planning of remedial operations to restore the annular barrier.
Increased ROP by 18% in Norway and in Other Applications through Optimizing Cutter Geometry from Laboratory Tests, Numerical Models and Field Tests
Authors: Izbinski Konrad , Cardoe Jennifer , Bomidi John
Published: February 2019

The oil-and-gas drilling industry has been utilizing modified PDC cutter geometry for improving performance. One of the first reinforcements of beliefs in positive effects of edge geometry changes was in report by Lin et al. in 1992 from conducting laboratory experiments on cutters. Currently, certain geometries are being favored based on limited testing and analysis of the design space. The detailed effect of geometry on attributes such as strength, cutting, wear and the tie to performance has not been fully understood.

This paper reports results of laboratory studies, numerical models, and field runs towards building such understanding. Single cutter edge-loading tests, pressurized cutting and wear tests were carried out alongside full-scale PDC bit tests and field runs. Improved analysis techniques were utilized to extract meaningful information from the tests. Numerical models were used to exploit the design space for the geometry.

The optimized geometry was selected with greater than 50% strength improvement as indicated by the numerical model. For the optimized geometry, pressurized single cutter lab tests indicated greater than 25% performance improvement in several aspects. Of the field runs in various applications, the largest dataset was in Norway with an ROP increase of 18% among greater than 187 bits run. This study is part of a holistic approach to understanding the thermo-mechanical behavior of PDC cutter drilling as it applies to improving design as demonstrated and drilling practices.

The improved cutter geometry has helped customers drill further and faster, which has helped reduce the cost of drilling. There are still improvements that can be made to cutter geometries that will push performance even further. The methods discussed in this paper will help expedite the learning process and help build better insights.
Field-Verified Modeling Compares Weight Transfer Methods in Horizontal Wells
Authors: Jesus Garcia , Sarah Banks , John McCormick , Robert Brosig
Published: February 2019

This paper describes a field-verified model that predicts weight transfer effects for three common techniques—axial vibration tools (AVTs), non-rotating protectors (NRPs) and pipe rocking from the surface (top drive oscillations). Friction has a large effect on drilling horizontal wells, especially while slide drilling. This paper discusses the use of as-drilled well data to assess the individual and collective effects of these drag-reduction methods. Prior to drilling the wells, these methods can be used in torque and drag engineering software models to more accurately predict challenges and feasible lateral lengths. Using these modeling techniques, it is demonstrated through several case histories that operators can effectively plan horizontal wells with longer lateral lengths; in other words, it can be analyzed if drilling the well is technically possible and economically feasible.
Experimental Studies on Cement Sheath Integrity During Pressure Cycling
Authors: Vrålstad Torbjørn , Skorpa Ragnhild , Werner Benjamin
Published: February 2019

Cement sheaths are among the most important barrier elements in petroleum wells. However, the cement may lose its integrity due to repeated pressure variations in the wellbore, such as during pressure tests and fluid injections. Typical cement sheaths failure mechanisms are formation of radial cracks and microannuli, and such potential leak paths may lead to loss of zonal isolation and pressure build-up in the annulus. To prevent such barrier failures, it is important to study and understand cement sheath failure mechanisms.

This paper describes a series of experiments where we have used a tailor-built laboratory set-up to study cement sheath integrity during pressure cycling, where the set-up consists of down-scaled samples of rock, cement and casing. Cement integrity before and during casing pressurization is characterized by X-ray computed tomography (CT), which provides 3D visualization of radial cracks formed inside the cement and rock. We have studied how contextual well conditions, such as rock stiffness, casing stand-off and presence of mudfilm, influence cement sheath integrity.

The results confirm that the rock stiffness and casing stand-off determine how much casing pressure the cement can withstand before radial cracks are formed in the cement sheath, where the rock stiffness is significantly more important than casing stand-off. Furthermore, it is seen that the radial cracks in the cement sheath continue into the rock as well. However, when a thin mudfilm is present at the rock surface, the cracks stop at the cement-rock interface, and the cement sheath withstands less pressure before failure. The bonding towards the rock is thus of importance.
Understanding Hydraulics and Friction Loss in Extremely Narrow Annuli for Deepwater MPD Operations
Authors: Patil Harshad , Deshpande Kedar , Smelker Keith , Naphade Pravin
Published: February 2019

Estimating hydraulic frictional loss in narrow annuli is challenging, especially for deepwater offshore wells with extremely narrow drilling margins. The challenge arises from annuli that are formed by big bore packers like Gravel Pack Packers, where the annular clearance isextremely small. In cases where open hole completions are run with MPD (Managed Pressure Drilling), the well typically would be displaced to heavier weight fluids before the packer is set and MPD is isolated. This paper illustrates the complications and limitations for estimating friction loss due to the narrow annuli when using drilling hydraulic programs.

Accurate estimation of hydraulic friction loss is extremely essential when using MPD system to maintain BHP(bottomhole pressure) while drilling, tripping, cementing etc. While drilling, the hydraulic models would typically be calibrated to PWD (pressure while drilling) in the BHA (bottomhole assembly), but when running liners, casings or completion systems, the lack of PWD complicates hydraulics and friction loss estimations. This phenomenon is accentuated when displacing the well from lighter drilling fluids to heaviercompletion fluids,especially when the completion fluid reaches the narrow annuli and displays sudden increase in frictional loss value due to the hydraulic model limitations.

This paper focuses on the limitations of estimating the frictional loss in narrow annulus created by the Gravel Pack Packers,when predicted using the drillinghydraulicmodels, and proposes a solution for mitigating such anomalies in calculations. To assess the sudden changes in the pressure loss estimations, the paper further utilizes CFD (Computational Fluid Dynamics) and the frictional loss estimations in these narrow annuli. As an outcome of the study, the paper proposes unique solutions to estimate the frictional pressure loss due to narrow annuli.
Effectiveness of rituximab in neuromyelitis optica: A meta-analysis
Authors: Gao Fulin , Chai Bingyan , Gu Cheng , Wu Ruipeng , Dong Tong , Yao Yuping , Zhang Yi
Published: February 2019

Background: Neuromyelitis optica (NMO) is a severe inflammatory autoimmune disorder of the central nervous system and often results in paralysis or blindness. Rituximab (RTX) is a mouse–human chimeric monoclonal antibody specific for the CD20 antigen on B lymphocytes and used to treat many autoimmune diseases. Disability and relapses were measured using the Expanded Disability Status Scale (EDSS) and annualized relapse rate (ARR) ratio to evaluate the effectiveness of RTX. This review performed a meta-analysis of the efficacy of RTX in NMO.
Methods: We searched through the databases of PubMed, Embase, and Cochrane Library. We compiled 26 studies, in which 18 used ARR ratio, 22 used EDSS score, and 14 used both variables. Differences in the ARR ratio and EDSS score before and after RTX therapy were used as the main efficacy measures. Publication bias was evaluated after the consistency test, and a sensitivity analysis was performed with mean difference (MD) of the efficacy of RTX.
Results: A meta-analysis of 26 studies with 577 participants was conducted. Antibodies against aquaporin-4 autoantibody were recorded in 435 of 577 (75.39%) patients with NMO. RTX therapy resulted in a mean (WMD) −1.56 (95% CI, −1.82 to −1.29) reduction in the mean ARR ratio and a mean (WMD) −1.16 (95% CI, −1.36 to −0.96) reduction in the mean EDSS score. A total of 330 of 528 patients (62.9%) reached the relapse-free state. A total of 95 of 577 (16.46%) patients had adverse reactions.
Conclusions: RTX has acceptable tolerance, reduces the relapse frequency, and improves disability in most patients with NMO. Future studies should focus on reducing the health-care costs, improving the functional outcomes, and reducing the adverse effects associated with RTX treatment.