bluuebunny/crossref_metadata_2025 huggingface dataset:
Vessel speed restrictions reduce risk of collision‐related mortality for North Atlantic right whales
Authors: Conn P. B. , Silber G. K.
Published: April 2013

Collisions with vessels are a serious threat to a number of endangered large whale species, the North Atlantic right whale (Eubalaena glacialis) in particular. In late 2008, the U.S. National Oceanic and Atmospheric Administration issued mandatory time‐area vessel speed restrictions along the U.S. eastern seaboard in an effort to mediate collision‐related mortality of right whales. All vessels 65 feet and greater in length are restricted to speeds of 10 knots or less during seasonally implemented regulatory periods. We modeled mortality risk of North Atlantic right whale when the vessel restrictions were and were not in effect, including (1) estimation of the probability of lethal injury given a ship strike as a function of vessel speed, (2) estimation of the effect of transit speed on the instantaneous rate of ship strikes, and (3) a consideration of total risk reduction. Logistic regression and Bayesian probit analyses indicated a significant positive relationship between ship speed and the probability of a lethal injury. We found that speeds of vessels that struck whales were consistently greater than typical vessel speeds for each vessel type and regulatory period studied; a use‐availability model fit to these data provided strong evidence for a linear effect of transit speed on strike rates. Overall, we estimated that vessel speed restrictions reduced total ship strike mortality risk levels by 80–90% with levels that were closer to 90% in the latter two of the four active vessel speed restriction periods studied. To our knowledge, this is the most comprehensive assessment to date of the utility of vessel speed restrictions in reducing the threat of vessel collisions to large whales. Our findings indicate that vessel speed limits are a powerful tool for reducing anthropogenic mortality risk for North Atlantic right whales.
Optimal Well Placement of Usari 37B using Dynamic Data, a Material Balance Model and Simulation Results
Authors: Onwude R. J. , Obasanjo O. , Udoh E. , Ajayi O. , Brock W. R. , Chen L.
Published: April 2013

The Usari Intermediate reservoirs field study completed in 2006 identified several significant opportunities. One of these, a drillwell opportunity in the 5-US reservoir, carried a substantial uncertainty in remaining oil volumes and thus, economic viability. No penetration existed to allow confirmation of the oil column thickness or position prior to drilling.

Material balance and numerical simulation were used to estimate the current OWC. The varied results from material balance, numerical simulation and geological evaluation formed the range of outcomes to optimally place the pilot hole and horizontal landing section to maximize recovery.

A pilot hole was drilled to intersect the range 7147' to 7190' of possible OWC depths. The OWC was found to be very close to the most likely contact scenario. Subsequently, the producing section was landed at the optimum location for maximum recovery. This led to a successful drillwell with an initial rate >8.5 kBD.

This paper will focus on how the uncertainty surrounding the remaining oil volume was addressed to obtain a successful drillwell.
Controlled Hydraulic Fracturing of Naturally Fractured Shales - A Case Study in the Marcellus Shale Examining How to Identify and Exploit Natural Fractures
Authors: Ciezobka Jordan , Salehi Iraj
Published: April 2013

This case study will illustrate how natural fractures were identified in real time through analysis of surface pumping parameters and confirmed with microseismic data and multiple production logs. Furthermore, subsurface natural fracture distribution will be examined in an approximately 1 square mile area using microseismic and production data. Additionally, gas shows from mud logs will be examined and correlated to production. Finally, methods for real-time fracture optimization will be explored based on natural fracture identification through analysis of fracturing parameters along the horizontal wellbore.

It is well known in the oil and gas industry that natural fractures, either open or prone to opening during hydraulic fracturing, greatly improve hydrocarbon production in tight sand and shale reservoirs. There are many techniques available to identify natural fractures; including image logs, mud logs, G-function analysis leading to pressure dependent leakoff (PDL), core analysis, and many more. However, these techniques have many limitations when used for optimizing the interaction of hydraulic fractures with natural fractures to create a complex fracture network. The limitations result from small sample size when using core analysis, inaccurate or unpredictable measurements from mud logs; or in the case of horizontal image logs, they are extremely costly and uneconomical to run regularly. Recent research related to subcritical index testing has shown that subterranean natural fractures manifest themselves in clusters that are not uniformly distributed along a horizontal wellbore. Therefore, it would be advantageous to gain insight into natural fracture occurrence and distribution before designing the fracturing program and then positively identify natural fracture clusters along the horizontal wellbore in real time and optimize hydraulic fracturing parameters on-the-fly.
Adsorption kinetics and thermodynamics of hydrophobic natural organic matter (NOM) removal from aqueous solution by multi-wall carbon nanotubes
Authors: Naghizadeh A. , Nasseri S. , Rashidi A. M. , Rezaei Kalantary R. , Nabizadeh R. , Mahvi A. H.
Published: April 2013

The objective of this research was to study the efficiency of Multi-Walled Carbon Nanotubes (MWCNTs) for the adsorption of hydrophobic natural organic matter (NOM) from aqueous solution under different operational conditions of contact time, pH, initial concentration of NOM and temperature. MWCNTs were synthesized via chemical vapor deposition (CVD) with average diameter of 10–50 nm. The results illustrated that both as-prepared and functionalized MWCNTs showed high adsorption capacity for the NOM studied. Functionalization of MWCNT affected the surface area and introduced oxygen-containing functional groups to the surface of MWCNT which depressed the adsorption of NOM onto MWCNTs-COOH. The obtained data were studied using Freundlich, Langmuir and BET isotherms; NOM adsorption data had the best conformity to the Freundlich isotherm. Kinetic studies were performed and the adsorption kinetics successfully followed the pseudo-second-order kinetic model. Thermodynamic parameters such as free energy change (ΔG°), enthalpy change (ΔH°) and entropy change (ΔS°) were determined and evaluation of them showed that the adsorption process for NOM is general spontaneous, endothermic and thermodynamically favorable.
Effect of seasonal climatic variance on water main failure frequencies in moderate climate regions
Authors: Fuchs-Hanusch D. , Friedl F. , Scheucher R. , Kogseder B. , Muschalla D.
Published: April 2013

The yearly water main failure frequency is a central performance indicator to describe the structural quality of a water distribution network. Besides age related deterioration, events such as severe climatic conditions or intensified third party construction may cause sudden seasonal increases in failure frequency trends. For the cold regions of Canada and the dry regions of Australia, several studies exist describing the impacts of climatic failure frequencies on water main failure variations. Failure prediction modelling applied to Austrian supply systems have shown that irregularities in overall failure trends were not explainable with commonly used model covariates like material, vintage, diameter or the number of previous breaks. Analysing the monthly failure frequencies of several Austrian utilities, seasonal differences and variations in failure frequencies are recognizable. The research described in this paper therefore focused on analysing if climatic impacts are responsible for these variations. In a first step, climatic indicators, which are able to describe seasonal climatic variations in moderate climate regions, were derived. In a next step the correlation between summer and winter failure frequencies to these climatic indicators was analysed. The indicators taken into account were, e.g. the decisive freezing index (DFI), the summer rain deficit (RDs) or the amount of successive hot days (AHD). The research has shown that in all investigated climatic zones of Austria, the severity of the winter season influences failure frequencies. A dependency between winter failure frequency and the DFI was significant especially for rigid material types and for diameters up to 200 mm. So far, soil moisture effects have only shown a slight significance. Nevertheless, the indicator AHD has shown a correlation to failure frequencies in the dryer climate zones of Austria. This is of further interest as it is very likely that the AHD is going to increase due to climate change.
Treatment of agricultural drainage water via downflow hanging sponge system for reuse in agriculture
Authors: Fleifle Amr , Tawfik Ahmed , Saavedra Oliver C. , Elzeir Mohamed
Published: April 2013

Treatment of agricultural drainage water (ADW) in a down-flow hanging sponge (DHS) reactor has been investigated for a period of 1 y. The reactor was operated at different hydraulic retention times (HRTs) of 5.26, 2.63, and 1.5 h and corresponding organic loading rates (OLRs) of 2.01, 1.86, and 4.43 kg COD/m3 d, respectively. The results obtained indicated that, decreasing the HRT from 5.26 to 1.5 h negatively affected the chemical oxygen demand (COD) removal. Average COD percentage removal values dropped from 89.3 ± 5.4 to 72.2 ± 16% respectively. Total suspended solids (TSS) concentrations were reduced by 85.5 ± 8.3, 90.4 ± 2.1, and 91.4 ± 4.9 at HRTs of 5.26, 2.63, and 1.5 h, respectively. However, the nitrification efficiency was slightly decreased from 85.2 ± 17.4 to 82 ± 11.4% by decreasing the HRT from 5.26 to 1.5 h and increasing the OLR from 2.01 to 4.43 kg COD/m3 d, respectively. Likewise, reducing the HRT from 5.26 to 1.5 h exerted a slight negative effect on the removal of the total phosphorus (TP). Based on these results it is recommended to operate such a system at a HRT of 2.63 h and OLR not exceeding 2.0 kg COD/m3 d for providing an effluent quality complying with the standards regulating the use of treated wastewater for agricultural purposes.
Feed-forward coagulant control using online UV/Vis monitoring
Authors: Fabris Rolando , Chow Christopher , Dexter Rob , Colton Jason , Knoblauch John , Drikas Mary
Published: April 2013

Water quality from the Murray River, Australia, can vary considerably and is expected to become more challenging to treat due to recent drought followed by widespread flooding and future climate change impacts. Better tools are required to help plant operators maintain water quality. Morgan water treatment plant (WTP) operates overnight to take advantage of off-peak electricity, however the stop/start practices add an additional complication to accurate coagulant dosing. Online monitoring and feed forward prediction is ideal in these situations as it can provide information while there is still a chance to make adjustments, unlike the feedback (post-dosing) control achieved with many other methods. Using a multiport sampling arrangement, water quality was monitored at Morgan WTP for a 6 month period. Data were validated against other online parameters and laboratory measured samples. In a comparison of predicted versus actual plant dose, results showed that treatment was optimised when the plant dose was changed in response to product water quality deterioration and eventually matched the prediction, even though this was not known to the operators at the time. The software prediction demonstrated faster reaction to inlet water quality changes and can produce more stable treated water quality. The predicted dose was added to the operator's Supervisory Control and Data Acquisition (SCADA) system for several months as a real-time display to provide an additional tool to aid decision making and instill confidence in the resulting water quality.
Characterization of bacterial diversity in drinking water by pyrosequencing
Authors: Zhang Yan , He Qiang
Published: April 2013

Controlling microbial contamination of drinking water is critical to public health. However, understanding of the microbial ecology of drinking water remains incomplete. Representing the first application of high-throughput sequencing in drinking water microbiology, the objective of this study is to evaluate pyrosequencing as a high-throughput technique for the characterization of bacterial diversity in drinking water in comparison with conventional clone library analysis. Pyrosequencing and clone library analysis were performed in parallel to study the bacterial community composition in drinking water samples following the concentration of microbial biomass in drinking water with ultrafiltration. Validated by clone library analysis, pyrosequencing was confirmed as a highly efficient deep-sequencing technique to characterize the bacterial diversity in drinking water. Sequences of Alphaproteobacteria and Betaproteobacteria dominated the bacterial community in drinking water with Oxalobacteraceae and Methylobacteriaceae as the most abundant bacterial families, which is consistent with the prominent abundance of these populations frequently detected in various freshwater environments where source waters originate. Bacterial populations represented by the most abundant sequences in drinking water were closely related to cultures of metabolically versatile bacterial taxa widely distributed in the environment, suggesting a potential link between environmental distribution, metabolic characteristics, and abundance in drinking water.
Groundwater hydrochemistry in the crystalline laterites/forest loams of Kasargod district, Kerala, India
Authors: Akhil P. S. , Sumangala K. N. , Sujatha C. H.
Published: April 2013

Groundwater quality assessment for drinking and irrigation purposes in the specific hot spot areas of Kasargod District, Kerala, India, was conducted during July 2009 to January 2011. Groundwater samples were examined and quantified for the major cations and anions, microbiological parameters, irrigation quality parameters such as sodium adsorption ratio (SAR), residual Mg/Ca ratio and %Na. Most of the ground samples were acidic in nature and the fluoride concentrations exhibited below the desirable limit. Concentration of iron exceeds the desirable limit of 0.3 mg/l during monsoon 2009 and pre-monsoon 2010. The competitive and non-competitive ion relationship between the major ions was authenticated by the correlation study.
The settlement Cernavoda III culture on the site Bubanj near Nis
Authors: Milanovic Dragan
Published: April 2013

Archaeological investigations carried out between 2008 and 2010 in the east
sector of site Bubanj near Nis (Plan 1; Figs. 1-3) confirmed the existence of
horizon of the Cernavoda III culture. In features 22, 23 and 31, which are
the remains of settlement buildings, have been found archaeological material
mostly pottery vessels, which according to style of decoration, technological
and morphological characteristics could be ascribed to the initial period of
late Eneolithic. Also, the dwelling structures of Krivodol-Salcu?a-Bubanj
cultural complex have been recorded in the layer of brown soil with the
remains of above mentioned Cernavoda III buildings. In the vertical
stratigraphy of trench I (Fig. 4) the mentioned layer was encountered
immediately under the layer of whitish/gray ashy soil and thin layer of
compact soil of gray color (Fig. 5), which date from the advanced phases of
the late Eneolithic and above the early Eneolithic layers. The settlement
features recorded during 2009 excavations are parts of the structures from
the settlement of Cernavoda III culture (Fig. 6; T. I-III). Feature 22 is
section of devastated probably aboveground building, feature 23 is shallow
pit and feature 31 is most probably the rubbish pit. Very similar
stratigraphy of the site had been recorded by investigations of M. Garasanin
in 1954. In the layer of brown soil, the material of Cernavoda III culture
was discovered in level III, and in level IV both Cernavoda III and the
material of the earlier Krivodol-Salcu?a-Bubanj cultural complex was
recorded. These building horizons are at different depths within
approximately same area of the trench and have been identified on the basis
of considerable amount of daub and stone, two floor levels, wooden building
material and fragmented pottery vessels (T. IV-VI). Despite the lack of
technical field documentation remains of one above ground structure could be
identified at level III according to descriptions from field journal from
1954. Certain finds from level IV indicate that remains of some floors from
this level could perhaps be associated with structure from the settlement of
Cernavoda III culture. Insufficient investigations and small quantity of
published material from the settlements of this period and mostly
singlelayered sites with poorly preserved cultural layer resulted in the fact
that in certain areas there are only indications for the settlements. The
position of the site at Bubanj suggests the importance of controlling the
zone of confluence of the Nisava River and the South Morava River where from
the roads branched toward north, south, west and east along the river
valleys. The investigations of prehistoric settlements carried out so far at
the site Bubanj confirm that areas of the Nisava and South Morava valley had
been included in the cultural complex Cernavoda III- Boleraz, which covers
rather large part of southeast and central Europe.
The Roman settlement on Gamzigrad prior to the imperial palace Felix Romuliana
Authors: Petkovic Sofija
Published: April 2013

The existance of the earlier Roman settlement which arose before the
construction of Galerius? palace Felix Romuliana was confirmed by
archaeological research. The traces of earlier buildings, constructed from
the end of 2nd to the end of 3rd century, were discovered inside the
fortified imperial residence: 1. three-naved building south from the ?Large
temple?, 2. the building below the earlier southern tower of the East gate,
3. the large building beneath the Galerius? baths and 4. the building in
front of the later southern tower of the West gate. Roman settlement from the
3rd century at Gamzigrad could be one of the mining - metallurgical and
commercial centers (vici, civitas) in the Timok Valley.
Ceramic crustulum with the representation of Nemesis-Diana from Viminatium: A contribution to the cult of goddess nemesis in roman provinces of Central Balkans
Authors: Gavrilovic Nadezda
Published: April 2013

The analysis of iconographic representation from ceramic medallion/cast for
cakes (crustulum) from Viminatium showed that we are dealing with a very rare
type of iconographic representation of goddess Nemesis-Diana. The monuments
with syncretistic presentation of goddess Nemesis-Diana are not only very
rare, but they imply a very close connection of the goddess with imperial
cult and with games and gladiator fights in amphitheatre. Overview and
analysis of all so far known cult monuments of goddess Nemesis, opened a
question about the correlation of goddess and presumed amphitheatre in
Viminatium and also a question about new aspect of honouring Nemesis in the
territory of Roman provinces of Central Balkans - as a patroness of agonistic
competitions and protectress of gladiatorial games and gladiators.
Römerzeitliche keramik aus dem nordöstlichen Turm der Römerstadt Horreum Margi
Authors: Petkovic Sofija , Tapavicki-Ilic Milica
Published: April 2013

Cuprija, die ehemalige R?merstadt Horreum Margi, liegt im zentralen Teil
Serbiens, an der M?ndung des Flusses Ravanica in die Morava. Der Ort war ein
Milit?rlager und spielte eine wichtige Rolle als Sammlungszentrum der
R?merprovinz Moesia Superior (Moesia Prima). Zwischen 1986 und 1990 fanden
die Ausgrabungen von Horreum Margi statt. Dabei wurden der Innenraum der
sp?tr?mischen Festung, die n?rdliche Mauer und der nord?stliche Turm
erforscht. W?hrend der Ausgrabung im Turm wurden unterschiedliche
Keramiktypen entdeckt. Sch?sseln (acht Typen) bilden dabei die Mehrheit.
Danach kommen T?pfe (sieben Typen), Amphoren (zwei Typen), Kr?ge (zwei
Typen), Deckel (ein Typ) und Becher (ein Typ). Sie geh?ren alle zu einer
komplexen sp?tr?merzeitlichen Typologie, die f?r diese Fundstelle erstellt
wurde und entsprechen zu den restlichen Keramiktypen, die im Festungsinneren
und entlang der Nordmauer ausgegraben kamen. Der Text bietet einen ?berblick
aller Keramiktypen an, die im nord?stlichen Turm der R?merfestung Horreum
Margi entdeckt wurden.
Geophysical survey at late roman Mediana
Authors: Milosevic Gordana , Peters Daniel , Wendling Holger
Published: April 2013

This article discusses the results of geophysical surveys conducted at
Mediana, near the town Nis (Serbia) in April 2010. The research was realized
in cooperation with the Romano-Germanic Commission of the German
Archaeological Institute, the Archaeological Institute and the University of
Belgrade. Mediana geomagnetic prospecting sites, as a form of non-destructive
methods of investigation, provided many new details about the architectural
and archaeological remains, particularly in the eastern part of the site.
From e- to m-Learning: Feasibility for an African-Delivered Tertiary Program
Authors: Benner Allison , Pence Alan
Published: April 2013

Since 2000, the Early Childhood Development Virtual University (ECDVU) has offered graduate-level programs in sub-Saharan Africa. These programs have been highly successful in creating a cadre of early childhood development (ECD) leaders in countries throughout Africa. When ECDVU was launched, the program was considered to be at the cutting edge in its use of appropriate and feasible technology. Within the past decade, however, the use of information and communication technologies (ICT), including mobile phones, personal digital assistants and tablets, has expanded dramatically within the Minority (‘Developed’) and Majority (‘Developing’) Worlds. Thus, ECDVU has begun to explore whether and how the graduate-level ECDVU programs might be delivered partially or primarily through tablets or smartphones.
Taking Advantage of Alice to Teach Programming Concepts
Authors: Biju Soly Mathew
Published: April 2013

Learning the fundamentals of programming languages has always been a difficult task for students. It is equally challenging for lecturers to teach these concepts. A number of methods have been deployed by teachers to teach these concepts. This article analyses the result of a class test to identify fundamental programming concepts that students have difficulty in understanding. On the basis of this result, an open educational resource, ‘Alice’, was introduced in the class along with C++ in the following semester. This article also provides a sample lecture that was designed using Alice and that corresponded to the objectives of the subject. The objectives of the subject were taken into consideration while designing the lectures, labs and assignment tasks using Alice. Students enrolled in Applied Programming in Summer 2010 were tested on the concepts after the introduction to Alice, and the results were compared with those of Summer 2009, where the traditional style of teaching programming was followed. Analysis of the results shows that Alice is very effective for teaching students programming concepts.
Redeploying the Transnational Framework for e-Learning Technologies as a Tool for Evaluation
Authors: Graham Deryn
Published: April 2013

Evaluation of ‘e-Learning’, or arguably ‘e-Delivery’, is difficult. One reason is that comparisons are often made between different courses delivered using various delivery modes, making such comparisons hard to justify. The Business School at a university in the United Kingdom reportedly delivers the same postgraduate course using two delivery mechanisms: (1) face-to-face (f2f) and blended, and (2) purely e-Delivery (online). The use of the proprietary Virtual Learning Environment (VLE) software WebCT for both modes of course delivery (f2f and online) lends a blended flavour to the f2f delivery mode, whilst the use of some f2f delivery for the online mode via WebCT also makes the online mode blended. The same postgraduate course delivered using the two mechanisms of f2f and online presents a true opportunity to compare and evaluate the different delivery modes. A second difficulty in the evaluation of course delivery mechanisms is the availability of an appropriate evaluation method and appropriate criteria. The following article describes the course, the evaluation method and criteria, the results of their independent application and any conclusions that may be drawn with respect to both the course and its delivery methods, and the evaluation methodology applied.
Blended Identities: Identity Work, Equity and Marginalization in Blended Learning
Authors: Heikoop Will
Published: April 2013

This article is a theoretical study of the self-presentation strategies employed by higher education students online; it examines student identity work via profile information and avatars in a blended learning environment delivered through social networking sites and virtual worlds. It argues that students are faced with difficult choices when having to present an online self to a group that has physical contact with each other. A virtual self that is accurate, ideal or drastically different from the offline self will be met with various methods of exclusion or marginalization according to dominant offline norms and expectations as well as online notions of strangeness and inauthenticity. This study demonstrates that in blended learning the issues students face with offline marginalization according to how identity is performed and read are, at best, equally represented online with an uncritical self-representation and, at worst, compounded online when critical self-representation is met with resistance.
Remix Revisited: Critical Solidarity in Youth Media Arts
Authors: Jocson Korina M.
Published: April 2013

This article explores youth making media across genre practices. The author begins with adiscussion of youth media arts, followed by a discussion of remix in the digital era. An exemplary video poem project from the San Francisco Bay Area is described to illustrate the importance of critical solidarity among youth. The multimodal design, production and distribution of ‘Slip of the Tongue’ suggest the potential of youth filmmaking to reach a worldwide audience through event screenings, film festivals, personal websites and social media sites. A close analysis of the video poem made by a 16- year-old Chinese American high school student brings to light a variety of stylistic choices that render youth-made films not only a product of identity, but also a form of social critique and action. Finally, the author discusses practical implications of critical solidarity for educators and youth advocates around the globe.
Learning Outcomes and Knowledge Sharing Using Web-Based Technologies in Finnish Forest Education from an Educational Experience Point of View
Authors: Xia Belle Selene
Published: April 2013

Learning outcomes, as a conceptual base, are a recognised phenomenon in higher education. Advances in technology, such as web-based technologies in teaching, have facilitated learning efficiency, while such technologies relation to learning outcomes remains a popular topic of research. In this article, we have employed the feedback of 312 Finnish university and polytechnic students in forest study programmes in order to assess alternative modes of learning using content analysis. In addition, we will evaluate learning outcomes and the level of knowledge sharing using web-based technologies in teaching under different educational experiences based on the interview results from the selected samples. Consequently, we aim to consolidate the concept of learning outcomes through a discussion of a virtual learning environment and the role of a facilitator in an optimal educational experience. We conclude that the concept of learning outcomes is multifaceted and the benefits of using web-based technologies in teaching are potentially great in Finnish forest education.
Interfacial Nanoleakage and Bonding of Self-Adhesive Systems Cured with a Modified-Layering Technique to Dentin of Weakened Roots
Authors: Mobarak E , Seyam R
Published: April 2013

Objective

The purpose of the study was to evaluate the nanoleakage and bond strength of different self adhesive systems cured with a modified-layering technique (MLT) to dentin of weakened roots.

Methods

Twenty-one maxillary incisors were decoronated and then root canals were instrumented and obturated with the cold lateral compaction technique. Weakened roots were simulated by flaring root canals until only 1 mm dentin thickness remained. Teeth were distributed into three groups. The canals were backfilled with Vertise Flow (VF group), a self-adhering system, following a modified-layering technique using two light-transmitting posts, sizes 6 and 3. DT Light Post size 2 was cemented using the same material. Remaining roots were prepared and cured in the same way as the VF group. However, in the TS/MF group, Clearfil Tri-S Bond (TS) adhesive and Clearfil Majesty Flow (MF) composite were used, while in the ED/PF group, ED primer II (ED)/Panavia F2.0 (PF) were used. After one week of storage, each root was sectioned to obtain six slices (two slices from each root third: coronal, middle and apical) of 0.9 ± 0.1 mm thickness. Interfacial nanoleakage expression was analyzed using a field emission scanning electron microscope (FEG-SEM), and the micro push-out bond strength (μPOBS) was measured at different root regions. Modes of failure were also determined using SEM. Data were statistically analyzed using two-way analysis of variance with repeated measures and Tukey post hoc test (p≤0.05).

Results

With MLT, all adhesive systems showed nanoleakage. For μPOBS, there was a statistically significant effect for adhesive systems (p<0.001) but not for root region (p<0.64) or for their interaction (p=0.99). Tukey post hoc test revealed that the bond strength of the VF group was significantly higher than the TS/MF and ED/PF groups for all root regions.

Conclusion

All of the tested self-adhesive systems cured using MLT had slight nanoleakage and were not sensitive to root regional differences. Self-adhering systems had higher bond strength than self-etch adhesives.
Physical Property Evaluation of Four Composite Materials
Authors: Chang M , Dennison J , Yaman P
Published: April 2013

Purpose

The purpose of this study was to evaluate the physical properties of current formulations of composite resins for polymerization shrinkage, surface hardness, and flexural strength. In addition, a comparison of Knoop and Vickers hardness tests was made to determine if there was a correlation in the precision between the two tests.

Materials and Methods

Four composite resin materials were used: Filtek LS (3M-ESPE), Aelite LS (Bisco), Kalore (GC America), and Empress Direct (Ivoclar). Ten samples of each composite (shade Vita A2) were used. Polymerization shrinkage was measured with the Kaman linometer using 2-mm-thick samples, cured for 40 seconds and measured with digital calipers for sample thickness. Surface microhardness samples were prepared (2-mm thick × 12-mm diameter) and sequentially polished using 600-grit silicone carbide paper, 9 μm and 1 μm diamond polishing solutions. After 24 hours of dry storage, Knoop (200 g load, 15 seconds dwell time) and Vickers (500 g load, 15 seconds dwell time) hardness tests were conducted. Flexural strength test samples (25 × 2 × 2 mm) were stored in 100% relative humidity and analyzed using a three-point bending test with an Instron Universal Testing Machine (Instron 5565, Instron Corp) applied at a crosshead speed of 0.75 ± 0.25 mm/min. Maximum load at fracture was recorded. One-way analysis of variance and Tukey multiple comparison tests were used to determine significant differences in physical properties among materials.

Results

Filtek LS had significantly lower shrinkage (0.45 [0.39] vol%). Aelite LS demonstrated the greatest Knoop surface hardness (114.55 [8.67] KHN), followed by Filtek LS, Kalore, and Empress Direct (36.59 [1.75] KHN). Vickers surface hardness was significantly greater for Aelite LS (126.88 [6.58] VH), followed by Filtek LS, Kalore, and Empress Direct (44.14 [1.02] VH). Flexural strength (MPa) was significantly higher for Aelite LS and Filtek LS (135.75 [17.35]; 129.42 [9.48]) than for Kalore and Empress Direct (86.84 [9.04]; 92.96 [9.27]). There is a strong correlation between results obtained using Knoop and Vickers hardness tests (r=0.99), although Vickers values were significantly greater for each material.

Conclusion

Results suggest that Aelite LS possesses superior hardness and flexural strength, while Filtek LS has significantly less shrinkage compared with the other composites tested.
Effect of a Chlorhexidine-containing Adhesive on Dentin Bond Strength Stability
Authors: Sabatini C
Published: April 2013

Purpose:

The present study aimed to investigate a novel adhesive system containing 0.2% chlorhexidine digluconate (CHX) for its ability to improve the stability of the adhesive interface compared with the use of 2% CHX as a therapeutic primer. Furthermore, the study aimed to confirm the inhibitory properties of these CHX concentrations (0.2% and 2.0%) on dentin matrix metalloproteinase activity by gelatin zymography.

Methods:

Superficial dentin substrate for bonding was obtained from 120 non-carious human molars. A conventional adhesive Peak LC Bond and a CHX-containing adhesive Peak Universal Bond were used either in combination with 35% phosphoric acid (etch-and-rinse approach) or with self-etching primer (self-etch approach) for evaluation of the variables CHX treatment (2.0% therapeutic primer and 0.2% adhesive), adhesive approach (etch-and-rinse and self-etch), and storage time (24 hours and six months). A bonding jig was used to fabricate composite cylinders, which were stored for either 24 hours or six months, after which shear bond strength (SBS) was evaluated using a notched-edge testing device. A three-way analysis of variance and a Student t-test with a significance level of p<0.05 were used to analyze the data. Extracts from concentrated demineralized human dentin powder were subjected to sodium dodecyl sulfate polyacrylamide gel electrophoresis and incubated in the presence of 0.2% and 2.0% CHX.

Results:

No significant effect of CHX treatment, adhesive approach, storage time variables, or their interactions on mean SBS was demonstrated (p<0.05). No significant difference between the control and the CHX-treated groups was detected for either adhesive technique at 24 hours or six months (p<0.05). No significant variation in mean SBS was detected after six months of storage (p<0.05). Zymographic analysis revealed bands of enzymatic activity for the group demineralized with phosphoric acid and complete inhibition of gelatinolytic activity for the groups treated with 0.2% and 2.0% CHX.

Conclusions:

CHX demonstrated inhibition of dentin proteolytic activity. However, when CHX was incorporated into a commercially available adhesive or used as a therapeutic primer, no difference in bond strength was observed at baseline or after six months of storage relative to the control group without CHX.
Pattern of Regional Metasteses in Laryngeal Carcinoma
Authors: Ahsan Ali Imam , Tarafder Kamrul Hasan , Rahman Sheikh Hasanur , Jamal Nasimul , Ali Syed Farhan , Yusuf Md Abdullah , Sarwar SM
Published: April 2013

Background: Regional metastases to the cervical lymph node is common in laryngeal carcinoma and this is also the most important prognostic factor of the disease. Objective: The purpose of the present study was to see the frequency of cervical metastases related to the sites of laryngeal carcinoma and also to see the relation between primary site and level of metastatic node as well as the relation between T and N stage of the tumour. Methodology: This cross sectional study was done in the Department of Otolaryngology and Head-Neck Surgery at Bangabandhu Sheikh Mujib Medical University, Dhaka and Specialized ENT Hospital of SAHIC, Dhaka from April 2009 to March 2010. A total number of 50 patients who were histopathologically proven laryngeal carcinoma at any age with both sexes were included in this study. General physical examination and ENT examination was done thoroughly. Direct laryngoscopy was done under general anaesthesia to assess the site, size, and extension of the tumour as well as for staging and biopsy. Results: A total number of 60% laryngeal carcinoma patients presented with regional metastases to the cervical nodes. Highest cases among laryngeal carcinoma were supraglottic carcinoma (72.0%) which also showed the highest rate of lymph node metastases (72.2%). Most frequently involved levels of the neck were level II (56.7%) and level III (33.3%). It was also observed that the rate of regional metastases was increasing with the advancing T-stage of the disease. Conclusion: Regional metastases is a useful prognostic indicator of the laryngeal carcinoma. So, early detection of the disease has a great importance on the management of the disease. DOI: http://dx.doi.org/10.3329/jssmc.v4i2.14406 J Shaheed Suhrawardy Med Coll, 2012;4(2):47-49
Study of Blood Glucose and Serum Calcium Level in Small For Gestational Age Babies
Authors: Mazumder Md Wahiduzzaman , Begum Nazma , Mannan MA
Published: April 2013

Background: Incidence of hypoglycemia in small for gestational age (SGA) babies is high. Therefore small for gestational age babies need close biochemical monitoring of blood glucose for early diagnosis and immediate management of hypoglycemia to prevent future neurodevelopmental outcome. Objectives: The study was designed to measure blood glucose and serum calcium level in new born babies with SGA and to compare with normal new born babies. Methodology: This case control study was done in Neonatology Department of BSM Medical University, Dhaka from 01 July to 31 December 2006. Low birth weight newborn babies with birth weight below 10th centile for gestational age were considered as SGA babies whereas babies with gestational age more than 37 completed weeks and weight more than 2500 gm were considered as control group. Results: Thirty two cases and equal number of controls were studied. Among 32 babies with SGA, hypoglycemia was found in 46.9% of cases and 3.1% cases in control group which was statistically significant (P<.05). Incidence of hypoglycemia was more during 0-12 hours (57.9%). Hypocalcaemia developed in 9.4% and 6.3% of SGA and control group respectively and difference was not statistically significant. Conclusion: Hypoglycemia was significantly more in small for gestational babies specially during 0-12 hrs of post natal life DOI: http://dx.doi.org/10.3329/jssmc.v4i2.14412 J Shaheed Suhrawardy Med Coll, 2012;4(2):50-52
Clinicopathological Study of 50 Cases Colorectal Carcinoma At Tertiary Care Hospital
Authors: Quddus Md Abdul , Alimunzzaman Md , Rahman Md Zilluar , Alam Md Kausar
Published: April 2013

Background: Colorectal carcinoma is a major causes of mortality and morbidity worldwide. Objective: The purpose of the present study was to consider the socio-demographic status and serum CEA level as diagnostic tool for advanced stages of colorectal cancer. Methodology: This analytical cross-sectional study was conducted in the Department of Surgery at Shaheed Ziaur Rahman Medical College Hospital, Bogra during the period of January 2010 to December 2011. Patients age ranged from 15 years to 75 years and above were included in this study. All efforts and available modern technologies including ultrasonography (USG), CT scan, endo-anal USG, chest X-ray were done to detect the primary site and metastasis of colorectal cancer. Result: The most frequent colorectal cancer was detected in 35-44 years age group with 60.0% male and 40.0% female patients. A total number of 41(82%) cases had been suffering from rectal carcinoma and 9(18%) with colonic cancer. Abdominal pain, anorexia, altered bowel habit, per rectal bleeding and abdominal lump were the cardinal features in clinical presentation. This study showed that serum CEA level was raised in 3(11.11%) cases with tumour size 2-5 cm and 21(91.30%) cases with tumor size >5cm. It was observed that serum CEA level was raised in 100% cases of Dukes stage 'D', 92.31% cases of stage 'C' and 30.56% cases of stage 'B' colorectal cancer. The serum CEA level in relation with tumour size and stage has been proved highly significant (p<0.001). Conclusion: Rectal carcinoma is found common than colonic cancer and level of serum CEA is directly related to the cancer stage. DOI: http://dx.doi.org/10.3329/jssmc.v4i2.14413 J Shaheed Suhrawardy Med Coll, 2012;4(2):53-56
Comparison Between Mercury and Liquid Crystal Forehead Thermometers for Measurment of Body Temperature
Authors: Rahman Nilufar , Kasem Fouzia Binte , Islam Md Reazul , Islam Md Rafiqul , Sultana Rezina , Matin Abdul
Published: April 2013

Background: Body temperature is a measure of the body's ability to generate and get rid of heat. For recording of body temperature several different types of thermometers are available, such as mercury thermometers, digital thermometer, liquid crystal forehead thermometer, and infrared tympanic thermometer are used. The accuracy of the device is to record and grade temperature is uncertain. Objective: The study was carried out the recordings of normal body temperature using liquid crystal forehead thermometer and compare with gold standard oral mercury thermometer. Methodology: Simultaneous recording were made using the two devise in randomly enrolled 150 apparently healthy medical student eighteen (18) to twenty (20) years age of either sex. Written & verbal consent was taken from the students without any coercion. Oraltemperature was recorded with Chinese made mercury thermometer and the forehead temperature was recorded using liquid crystal (Boots, UK) thermometer. Results: No statistical significant difference existed between the recordings of two devices. The mean difference was 0.8 degree. Liquid crystal forehead thermometer recorded higher temperatures. Both the devices recorded temperature within normal range. Conclusions: Sensitivity of liquid-crystal thermometer to detect body temperature is comparable with that of mercury thermometer. It is a good device for home use but health providers should not use it. Mercury thermometer remains the gold standard. DOI: http://dx.doi.org/10.3329/jssmc.v4i2.14421 J Shaheed Suhrawardy Med Coll, 2012;4(2):60-61
Umbilical endometriosis in a 39 years old parous woman: A Case Report
Authors: Ashraf Fatema , Yasmin Nilofar , Islam Jinnat Ara , Choudhury Farzana Rabee , Guha Kaberi
Published: April 2013

Endometriosis is a common gynaecological condition and presents mainly with involvement of the pelvic organs. However umbilical endometriosis is uncommon. A correct differential diagnosis can be difficult and the use of epiluminescence and MRI is suggested for the accuracy of preoperative diagnosis. This case report was experienced at a tertiary care hospital at Dhaka city. The patient was 39 years old multigravid woman presented with umbilical swelling and pain during menstruation for last 1year with cyclical bleeding from the umbilical region for last 4 months. The patient had regular menstrual bleeding since the time of menarche. The patient had no previous history of endometriosis, dysmenorrhea or dyspareunia. Physical examination showed a hyperpigmented tender paraumbilical swelling with bloody discharge through umbilicus. An accurate anamnesis and clinical examination together with the use of high resolution ultrasonography and fine needle aspiration cytology led to an accurate pre-operative diagnosis of umbilical endometriosis. The surgical approach to umbilical endometriosis represented an important step in achieving a satisfying result. The lesion to be excised and adequate umbilical repositioning was done. The patient was asymptomatic at the follow-up visit (12 months after surgery), however, nevertheless warned of the risk of recurrence. A natural-looking umbilicus was observed in cases with minimal visible scars DOI: http://dx.doi.org/10.3329/jssmc.v4i2.14423 J Shaheed Suhrawardy Med Coll, 2012;4(2):65-67
A 8 years Old Girl Presented with Parry Romberg Syndrome attended at Shaheed Suhrawardy Medical College Hospital: A Case Report
Authors: Khan Ehsanul Haque , Rashid MA , Moonmoon Taslima Hoq , Ahmed Monzur , Tanim Bidoura
Published: April 2013

Parry-Romberg Syndrome is an uncommon, degenerative and poorly understood condition. It is characterized by a slow and progressive atrophy affecting one side of the face. Possible factors that are involved in the pathogenesis include trauma, viral infections, heredity, endocrine disturbances and auto-immunity. Characteristically the atrophy progresses slowly for several years and soon after it become stable. In this case report, the patient of 8 years old girl complaints of gradual wasting of left side of face for 1 year involving cheek, chin, pre-auricular area, forehead, left upper lip which reveals facial asymmetry and mild wasting of left side of face as well as tongue. There was focal alopecia and depression over left side of scalp. After four months back, there was a hypopigmented area over malar prominence of same side. She was diagnosed as Parry Romberg syndrome on the basis of history, clinical examination and investigation. Antinuclear antibody and Anti-Scl-70 antibody were positive. Histopathological diagnosis was compatible with localized scleroderma. The patient was treated with drugs, physical therapy including electric stimulation as well as exercise. DOI: http://dx.doi.org/10.3329/jssmc.v4i2.14424 J Shaheed Suhrawardy Med Coll, 2012;4(2):68-71
Global Decrease of Histone H3K27 Acetylation in ZEB1-Induced Epithelial to Mesenchymal Transition in Lung Cancer Cells
Authors: Roche Joëlle , Nasarre Patrick , Gemmill Robert , Baldys Aleksander , Pontis Julien , Korch Christopher , Guilhot Joëlle , Ait-Si-Ali Slimane , Drabkin Harry
Published: April 2013

The epithelial to mesenchymal transition (EMT) enables epithelial cells with a migratory mesenchymal phenotype. It is activated in cancer cells and is involved in invasion, metastasis and stem-like properties. ZEB1, an E-box binding transcription factor, is a major suppressor of epithelial genes in lung cancer. In the present study, we show that in H358 non-small cell lung cancer cells, ZEB1 downregulates EpCAM (coding for an epithelial cell adhesion molecule), ESRP1 (epithelial splicing regulatory protein), ST14 (a membrane associated serine protease involved in HGF processing) and RAB25 (a small G-protein) by direct binding to these genes. Following ZEB1 induction, acetylation of histone H4 and histone H3 on lysine 9 (H3K9) and 27 (H3K27) was decreased on ZEB1 binding sites on these genes as demonstrated by chromatin immunoprecipitation. Of note, decreased H3K27 acetylation could be also detected by western blot and immunocytochemistry in ZEB1 induced cells. In lung cancers, H3K27 acetylation level was higher in the tumor compartment than in the corresponding stroma where ZEB1 was more often expressed. Since HDAC and DNA methylation inhibitors increased expression of ZEB1 target genes, targeting these epigenetic modifications would be expected to reduce metastasis.