bluuebunny/crossref_metadata_2025 huggingface dataset:
Normal faulting and role of the reverse drag in analyzing petroleum systems, an example of 2D modeling from the Nam Con Son Basin (Vietnam)
Authors: Spahic Darko , Vanin Valery , Perepelina Anastasia , Aryakbaeva Zhuldyz
Published: July 2015

The studied area is located around a margin of the Nam Con Son Basin (NCSB) (Vietnam). A 2D seismic interpretation data indicated two main structural domains that could influence the hydrocarbon distribution – hanging wall and footwall of the possible large-scale reverse drag. In this study by using Cenozoic petroleum systems modeling around a cluster of normal faults we investigate present day migration paths assessing the role of hanging wall and footwall domains in hydrocarbon exploration. In order to analyze fluid migration, we reconstructed burial history, timing of hydrocarbon generation, migration paths with emphasis on tectonic model further observing the present day hydrocarbon distribution. The complete results of the petroleum system modeling are presented by Spahić et al. (in press) whereby in this paper, we focus on the footwall domain of the main normal fault.

The studied section exhibited finite length faults that are associated with possibly two rifting phases, whereby the role of Master faults was separate to investigate fluid distribution. Faults are root in the basement propagating towards the higher sections. For the modeling, Paleogene Formations accommodated in near-shore and lacustrine environment are adopted as potentially the main source of the fluids. The higher sections are divided into the reservoir and trap systems and are tested for fluid migration using PetroMod 2012.2 (Mark of Schlumberger). Results indicate that main migrations routes could be associated with the main fault further distributing fluid across the investigated section. The two main structural domains, large-scale hanging wall and footwall most probably associated with the reverse drag developed around the main normal fault could be treated as a potential trapping mechanism. The computed migration paths pointed that not only well-known rollover anticlines could be recognized as a potential trap system, but also perspectives of the footwall domain could be further investigated.
Comprehensive Study on the Heterogeneity of Carbonate Reservoirs in Carboniferous at Eastern Area of Pre-Caspian Basin
Authors: Zhiqiang Xu , Shutang Jin , Hongtao Chen , Xin Shi , Jianhui Xue , Hulin Niu , Arkbar Erken Aikebaijiang , Margarita Bryzgalova
Published: July 2015

Carboniferous is one of the main hydrocarbon exploration and production sequence in North Teluwa area at the eastern region of Pre-Caspian basin (Fig.-1). The reservoir rocks in Carboniferous are composed mainly of limestone and dolomite overlaid by Permian pre-salt zone.

Petroleum exploration for carbonate reservoirs in the pre-salt Carboniferous sequences in study area inevitably faces the challenges as (1) pre-drilling, the structure traps' (leads') deformation caused by uneven seismic velocity through the salt zone has been misleading to drill false trap; (2) post-drilling, the heterogeneity of carbonate reservoir performance has been confusing for understanding and appraisal the reservoir.

Pre-stack depth migration of 3D seismic processing method combing with drilling data seems to have satisfied the exploration and development geologists since some appraisal wells completed here.

This study as a pilot testing experiment is mainly concentrated on the reservoir heterogeneity through integrated analyses of core, borehole imaging logging and combining with high resolution seismic technique equipped with Broadband, Wide azimuth and High density (BWH) acquisition and processing measures.

Core analysis reveals the mechanics and types of porosities in these carbonate reservoirs, and BWH information has been used to illustrate changes between wells. The study and analyses results are aimed at to provide reliable models for geologists and geophysicists when they are working on the data processing and interpretation and also might be as referential information for well testing and production engineers working on seismic inversion in reservoir prediction in this area.
A Mechanistic Study of IOR Processes for Naturally Fractured Reservoirs
Authors: Shie-Way Wang , Zhumagulov Kanat , Liu Ning , Villegas Mauricio
Published: July 2015

This study presents a process to investigate mass transfer between fracture and matrix in naturally fractured reservoirs. The study has three parts: (1) the effect of imbibition by capillary pressure Pc in matrix, (2) mass transfer between fracture and matrix through k*σ, and gravity drainage, and (3) combination of capillary pressure, gravity, and viscous forces.

The important results from this study are listed below.

Part-1: The counter current flow theory predicts the capillary pressure between two adjacent cells will have same value at equilibrium condition for both gas-oil and oil-water systems. In addition, the saturation in each cell has a tendency to approach a value where Pc=0 regardless the wettability of the Pc curve.

Part-2: Simulation shows injected fluid preferentially goes through high permeability fracture channel and mass transfer between fracture and matrix is mainly due to k*σ. Gravity drainage effect within a thick matrix block would be reduced due to low vertical permeability or k*σz. If k*σ=0, only viscous force is active.

Part-3: Initial estimate of critical water injection rate on oil recovery in field simulation can be calculated from dimensionless fracture capillary number derived from laboratory test. Then reservoir simulation is used to study the sensitivity of water injection rate to obtain optimal injection rate. In general lower injection rate would be favored due to lower viscous force and longer contact time with the matrix.
Unique Artificial Lift Solution for Complex Operation in a Caspian Sea Field Using Jet Pumps
Authors: Berdyev Yunus , El Habashy Ramy
Published: July 2015

Dragon Oil needed to extend the production lifetime for wells with lower than expected natural flow duration. After reviewing multiple options, Dragon Oil chose to implement artificial lift using jet pumps to return the candidate wells to the required production levels. This case study highlights the rationale, implementation, and outcomes from this additional well investment. Candidate wells for jet pump artificial lifting have been drilled from offshore wellhead platform 1 into the crest of the main reservoir production basin. A multiwell hydraulic jet pump system was installed during the spring of 2013.
Different Facies Modeling Techniques to Optimize HM, Late Visean, Karachaganak Field, Kazakhstan
Authors: Albertini C. , Bazzana M. , Bigoni F. , Francesconi A. , Pontiggia M. , Tarantini V. , Tumbarello G.
Published: July 2015

Karachaganak Field is an isolated carbonate bank consisting of Carboniferous to Lower Permian carbonate deposits located in the northern margin of the Pre-Caspian Basin of Kazakhstan. Discovered in 1979, it represents one of the largest gas and condensate reservoirs in the world and has been in production since 1985. This paper focuses on the different modeling methods applied to Late Visean sequence to try to improve the reservoir model reliability. In fact although this interval is relatively thin, it is mostly located inside the Oil Rim interval, so that it strongly impacts the present development phase which is focused on maximizing liquid recovery. This peculiar stratigraphic interval represents the highstand section of the Late Visean sequence and records the initial settling of micro-biohermal deposits constituted by in situ bryozoans, microbial boundstone, cementstone, all facies interlayered with crinoidal limestones. Due to its reduced thickness, there is a minimal contribution of the seismic sequence stratigraphy interpretation to understand the internal structure and geometry of this sequence. Despite its complexity, the Late Visean was initially modeled as a unique "undifferentiated body" characterised by the whole petrophysical data without discriminating the different depositional facies. Now, thanks to new core and analogue data, there is enough information to attempt to model this stratigraphic interval with a more detailed approach, trying to both reconstruct the 3D Facies distribution and utilize the relevant Reservoir Properties. Therefore two additional simulation methods have been tested: Object-Based Modeling and Multiple-Point Statistics Facies Modeling. Thanks to the long historical production, all these alternative scenarios have been compared to the initial SGS approach using the HM as benchmark to evaluate the best methodology to be applied.
Multi-Disciplinary Collaborative Pre-Caspian Shallow Subsurface Aquifer Study: Data Acquisition and Management, Petrophysical Interpretation, Static and Dynamic Modeling, and Volume Validation With Well Rest Data
Authors: Zhumagulova Akmaral , Baktybayeva Kalmpyr , Se Yegor , Katz Bodo
Published: July 2015

The development of the giant Tengiz and Korolev oil fields might require a large and reliable industrial water source for future development. This paper shares best practices from a multidisciplinary team effort in characterizing the shallow aquifer water sources in the Tengiz area. The data set above the Tengiz oil zone is characterized by limited cores and large number of penetrations with logs, as well as 3D seismic.

A subsurface study of the Tengiz area Post-Salt aquifers is challenging because of the old vintage of existing logs and limited core in shallower section of wells targeting Tengiz and Korolev oil reservoirs. A subsurface data gathering program was executed to acquire new logs, core from two new wells A-1 and B-1 from Alb-Cenomanian, Upper Neocomian, Aptian and Jurassic formations. All core and log data in conjunction with seismic improved our understanding of the depositional environments, connectivity and areal extend of numerous sand bodies. Core porosity and permeability very well match with new wireline logs. Based on information gained and new interpretation data, we now have better understanding of the geology of potential water source sands.

Alb-Cenomanian and Upper Neocomian deposits were found to be the two largest aquifers in the Tengiz area. The Alb-Cenomanian has high net-to-gross with extensive fluvial channel belt sandstones. Reservoir properties are very good and water volume is very large. The Upper Neocomian consists of ribbon-like fluvial channel belts (2-15m thick) embedded within floodplain deposits and interbedded thin (i.e., <2m) crevasse splay deposits. Reservoir sandstone is moderate to excellent quality. The Upper Neocomian has stratigraphic barriers above and below – internally it exhibits some baffles and barriers associated with floodplain shales. Aptian and Jurassic sections were evaluated to be unattractive as water sources. Because of sand quality and higher water volume, Alb-Cenomanian and Upper Neocomian formations were selected as the best candidates for water source.

New seismic interpretation, log and core data were incorporated to construct static models. Dynamic models for shallow aquifers are being built; the models will be used to support the industrial water source development plan for Tengiz and Korolev oil fields.
H2S Emergency Response Strategy & Evaluating Risk Reduction Measures
Authors: Geyer Tim , Sargent Diccen , Vignati Luca , Arnold Phil , Awad Sami , Wright Steve , Khan Murad , Hunter William , Daulova Gulnara
Published: July 2015

This paper presents the elements of KPO's field-wide H2S Emergency Response and Controls Strategy, together with an analysis to prioritise a variety of potential risk reduction measures.

Karachaganak Petroleum Operating B.V. (KPO) is the operator of the Karachaganak Field in Kazakhstan. The hydrocarbons produced are classified as sour, in that they contain approximately 4% - 6% Hydrogen Sulphide (H2S) by volume. At these concentrations, any unplanned release of production fluids could pose immediate danger to unprotected personnel due to the toxic nature of the gas. As such KPO requires effective decision-making support to assist in the management of safety and the prioritisation of capital expenditure, to discharge its obligation to ensure that risks are managed and controlled to levels which are as low as reasonably practicable.

A field-wide H2S Emergency Response and Controls Strategy has been developed and potential H2S related improvement options evaluated. This paper presents the elements of the strategy, comprising:

Hazard Identification and Risk Assessment ER Strategy and ER Planning POB Control and Personnel Tracking Hazardous Event Detection Annunciating the Alarm Emergency Communications Third Party Communications Escape Provisions Shelter in Place Search and Rescue Evacuation Training and Exercises Specialist Medical Facilities.

A high-level analysis was used to prioritise a variety of potential enhancement options (covering communications systems, gas detection, evacuation, etc). For each option, the measure, the safety benefits, other benefits, limitations, technical and commercial considerations, are highlighted.

This paper will contribute to the sector's definition of best practice in terms of risk reduction under sour production conditions, highlight new modern technology developments and show some solutions adopted from different industries.
Integrated Carbonate Clinoform Characterization Through Assisted History Matching of Wireline Formation Pressure Data, Karachaganak Field, Kazakhstan
Authors: Saduakassov Bekzhan , Yakhiyayev Nursultan , Uxukbayev Gadilbek , Kismanov Adilbek , Amangaliyev Bagdad , Burns Lucy , Baigazin Khakim
Published: July 2015

A sloping depositional surface, known as clinoform, is commonly associated with prograding strata deep into water and this surface can be imaged with seismic (J.L.Rich, 1951). During a sea level drop carbonate sediment factories tend to shut down and results in periods of non-deposition. These clinoform surfaces can be cemented, resulting in a partially sealing effect. Therefore characterizing clinoforms is crucial to better understand the reservoir dynamics and hydraulic communication throughout the field.

In the Karachaganak field, Wireline Formation Pressure acquisition along the sub-horizontal well section has played a major role in the identification of semi-transmissible flow restrictions in the field. In particular, plots of depth corrected pressure measurements against distance from wellhead showed clear discontinuities confirming the existence of pressure baffles. Once these clinoforms are identified, their properties have to be calibrated against the measured pressure data, process that historically has been implemented by manual trial-and-error approach which is time-consuming and often frustrating.

This paper proposes a methodology based on assisted history matching solutions to constrain the properties and sealing degree of clinoform's regions to both Wireline Formation and Static Bottom-Hole Pressure data. The proposed approach allows engineers to integrate geological and reservoir engineering workflows into a single model driven by state-of-the-art history matching optimization techniques. This makes possible to systematically sensitize the properties of the clinoforms assuring consistency between static and dynamic models.

As a result, observed pressure has been matched, and hence the characterization of the clinoforms properties was considerably improved in a short time compared with the timeframe required by the traditional manual approach. The presented workflow is a valuable tool to set methods and gain experience using assisted history matching techniques, and furthermore, it contributes to a change in history matching philosophy by semi-automating laborious tasks achieving faster and more physically coherent solutions.
Advanced Integrated Field Modelling Approach in Development Planning and Management of Giant Gas Condensate Field
Authors: Tleukhabyluly O. , Mutaliyev G. , Abdibapov A.
Published: July 2015

Over 60 % of the world's daily oil production today comes from giant fields, where production is on decline (Robelius, 2007). Extended development and management of such complex projects would require integrated and cost efficient approach.

While there are many theories on integration of reservoir and network models, there is very limited experience on the actual application of such models to field development plans (FDP) as routine decision making tools. This paper presents successful case study of creating robust and fast integrated model of a giant gas-condensate field with complex gathering network and processing facilities. Use of integrated asset modelling (IAM) approach has proven to bring value over conventional "standalone" modelling in this particular complex system. This system includes three inter-flowing processing facilities simultaneously constrained by processing capacities, gas compression for re-injection and overall export agreements. In addition, all the wells (about 100 producers and 20 injectors) have individual constraints (liquid rate and drawdown limits for producers, injection rate and pressure limits for gas re-injection wells).

Major technical challenges resulting from the complexity of such modelling were discussed here. Increase of stability (honouring all constraints), accuracy (reproducing actual data) and speed (4-5 min per timestep) were achieved by imbedding custom algorithms and workflows into IAM while using fully compositional Eclipse and complex GAP network models. One of the major challenges was to properly model and optimize inter-unit flows and properly prioritize low GOR wells.

In this paper a project from FDP is used as an example to demonstrate the benefits and limitations of integrated modelling approach. Based on the case study example the integrated model has proved to bring incremental value by providing more accurate production profiles and reducing development costs by avoiding "overdesigning". These and other conclusions are discussed in the paper in the context of the actual project.
System Design and Flow Assurance Implications of Hydraulic Submersible Pumps for Artificial Lift
Authors: Brook Graham , Lovick Jonathon
Published: July 2015

Hydraulic submersible pumps are an artificial lift mechanism that can be used as an alternative to gas lift or electric submersible pumps. This paper presents a method for the rigorous evaluation of hydraulic submersible pumps (HSPs) during the concept selection phase of a project. The method couples multiphase flow simulations with the operation of the pump and turbine to identify feasible system designs. The paper explains how the flow assurance engineer must consider the two new constraints of system design pressure and power water to produced fluid ratio when sizing multiphase flowlines, rather than the normal constraints of capacity, back-pressure and turndown. An example demonstrates why a holistic approach to the design of the system, from the sandface through to the production separator and incorporating the power water delivery system, is crucial in assessing concepts involving HSPs.

The introduction of large volumes of water into the production system presents new challenges to the management of flow assurance. The influence of emulsions, the potential advantages of lowering the fluid viscosity if operating in the water continuous phase and the impact on the processing facilities will all be discussed. Further advantages have been identified for fields with waxy crudes, where hot water can be used to drive the HSPs whilst introducing heat into the system. The results of detailed thermal-hydraulic modelling (using the transient multiphase flow simulator, OLGA) will be presented to demonstrate the feasibility of this approach.
Using Procedure Automation to Reduce Acid Gas Flaring
Authors: Fomina Marina
Published: July 2015

The current paper presents Acid gas flaring (AGF) project which is a "Containment Strategy" for reducing acid gas flaring. The project goal was to mitigate acid gas flaring for a single sulphur recovery unit trip. Acid gas flaring events introduce risks to personnel, impact the environment and may lead to negative operational and business outcomes. TCO implemented an automated procedure to address this problem with the goal to protect the personnel and environment, reduce operating impact and improve TCO’s reputation as a ‘good neighbor’ operating the facility.

The procedure was aimed to automate a sequence of coordinated moves across all five KTL trains. This involved decreasing sour gas and oil rates from all Crude Stabilization Units while using existing vessels to temporarily accumulate acid gas in the rich amine. Simultaneously field production was rapidly decreased by 30%. The intent of procedure was to prevent the acid-gas header pressure from rising to a point at which pressure control valves open to flare. This would ‘contain’ the acid gas thereby mitigating flaring.

TCO utilized the AGF procedure multiple times since 2012 to successfully mitigate flaring events.
Dynamic Multiphase Flow Simulation of Pigging One of Two Parallel Pipelines
Authors: Dosmukhamedova Karlygash
Published: July 2015

Current paper represents dynamic multiphase flow simulation applied to realistic transient scenario of pigging one of the two parallel 24-inch trunkline that transfer oil and gas production to Tengiz Second Generation Plant. Despite pigging is inevitable and required activity, it creates a big challenge for receiving facility causing inlet separators level fluctuations and as worst case Plant Emergency shutdown. OLGA dynamic simulation tool is able to predict multiphase flow behavior over required time and changed conditions (or inputs). This work was done to compare software predicted liquid slugs as pigging result versus real historical data. The consistency in results was reached by using accurate input data such as rigorous geometry, tuned fluid file for Tengiz oil, and accurate assessment of the real slugs. For instance, Plant separator level accumulation factor made both realistic and OLGA predicted trends really close to each other. Reached consistency gives a credit to use software for slugs prediction and creating according operational procedures to eliminate their impact to the Plant.
Hydrocarbon Emission Reduction: Application of an Integrated Solution to Separate and Treat Well Clean-up and Produced Water in the Karachaganak Field, Kazakhstan
Authors: Kaziyeva Indira , Saada Tamer , Hutson Peter , Frau Simone Andrea , Vegliante Enzo , Donohue Leo , Shektebayeva Raziya , Izbassov Arman
Published: July 2015

Minimising or eliminating completely the flaring of hydrocarbons during well clean-up and early production testing is an increasing challenge for the oil and gas industry and an important issue for Karachaganak Petroleum Operating b.v. (KPO).

KPO operates the giant Karachaganak gas-condensate carbonate reservoir located in north-western Kazakhstan. To improve reservoir management and field recovery, KPO drills long horizontal wells and then stimulates them with acid. KPO has used a variety of different acid stimulation techniques, progressing from simple acid washes to high rate matrix acid treatments and hydraulic fracturing with gelled acid. With the advent of mechanical downhole diversion equipment, KPO can now perform Multi-Stage Selective Acid Stimulation treatments. However, as the complexity of the stimulation techniques has increased, so has the volume of fluid injected into the wells, most of which is recovered to surface during the subsequent clean-up and well testing.

The processing facilities at Karachaganak are not designed to handle large quantities of water. A traditional approach to dealing with this problem would be to flare all the produced fluids from the wells until an acceptable water-cut of 1% is achieved. KPO recognised that it had to adopt a different methodology in order to reduce the volume of hydrocarbons flared during well clean-ups and testing. A new approach to well clean-ups was sought that would be capable of efficiently separating the fluids and measuring the flow-rates from high productivity wells and would:

Reduce or eliminate flaring. Reduce the environmental impact of well clean-up operations. Dispose of unwanted fluids in a safe and environmentally friendly manner. Recover additional hydrocarbons that would otherwise be flared.

This paper describes the evolution and application of a new approach to performing well testing, clean-up and water separation and treatment in the Karachaganak field. It describes the methodology, challenges and strategies that were adopted to manage the liquids produced during the clean-up and early testing of new Karachaganak wells. It focuses on the value brought to both the environment and the field by the deployment of an advanced, integrated 3 Phase High Pressure Separator (3P-HPS) spread with associated water treatment concept.
Productive characteristics and body measurements of alpine goats raised under smallholder production systems in central Serbia
Authors: Maksimovic N. , Bauman F. , Petrovic M.P. , Petrovic V.C. , Ruzic-Muslic D. , Micic N. , Milosevic-Stankovic I.
Published: July 2015

The purpose of this study was to evaluate present level of productivity and
determine linear body traits of Alpine goats raised in Serbia on smallholder
farms. Data were collected from 22 smallholder farms located in Belgrade
district, with total of 330 purebred Alpine does 2-9 years of age, 145
yearling does and 476 kids. Traits measured were: body weight of does, body
weight of kids at birth, 30 days of age and at weaning (90-120 days),
prolificacy of mature and yearling (primiparous) does, six linear body traits
of does (wither height, body length, hearth girth, chest depth, chest width,
pelvic width) and milk production (milk yield, milk fat and milk protein
content). The analysis showed the average body weight of does to be 54.96 kg,
while the average body weight of kids at birth, 30 days of age and weaning
was 2.73 kg, 8.7 kg and 18.3 kg., respectively. Prolificacy was 144% in
mature and 125% in yearling does. Measurements of linear body traits were:
wither height 67.87 cm, body length 71.92 cm, hearth girth 81.79 cm, chest
depth 32.93, chest width 21.49 cm and pelvic width 17.63 cm. Among dairy
production traits, following results were obtained: lactation length 220.73
days, total milk yield 531.66 kg, milk fat content 3.33% and milk protein
content 3.16%. It was concluded that the overall productivity of Alpine goats
raised under smallholder production systems in Serbia is satisfying. Giving
the fact that these animals are usually kept under poor conditions, many of
these productive traits are very good.
Application of talent and knowledge management in the Czech and Slovak Republics: First empirical approaches
Authors: Urbancová Hana , Vnoucková Lucie
Published: July 2015

This paper endeavours to extend existing theories on talent and knowledge
management by applying theoretical concepts on real management of
organisations. The examination of different definitions of talent management
and knowledge management is crucial for capturing their practical impact on
central human resource development practices such as education, training, and
development. The main aim of the paper is to identify key factors that
describe the main approaches to talent management (TM) and ensuring knowledge
continuity (EKC), based on analysis of current approaches of organisations in
the Czech and Slovak Republics. The results reveal three possible approaches
to employees and organisational development. The first type of organisation
develops employees within their own organisational rules, the second type of
organisation does not support development of employees in any way, and the
third type of organisation does not affect employees? development but the
employees develop themselves - these can be characterized as ?knowledge
employees?. The paper identifies the practical benefits for organisations
resulting from talent management and ensuring knowledge continuity. Knowledge
continuity and its development guarantee that knowledge is retained within an
organisation. Knowledge needs to be transferred to relevant successors who
can participate in a talent management programme.
Copolymers based on N-acryloyl-L-leucine and urea methacrylate with pyridine moieties
Authors: Buruiana Emil , Murariu Mioara
Published: July 2015

By using free radical polymerization of
(N-methacryloyloxyethyl-N?-4-picolyl)-urea (MAcPU) and N-acryloyl-L-leucine
(AcLeu), an optically active copolymer,
poly[(N-methacryloyloxyethyl-N?-4-picolyl)-urea-co-N-acryloyl-L-leucine],
MAcPU-co-AcLeu (1.86:1 molar ratio) was prepared and subsequently
functionalized at the pyridine-N with (1R/S)-(?/+)-10-camphorsulfonic acid
(R/S-CSA) and at carboxyl group with (R)-(+)-?-ethylbenzylamine (R-EBA) or
trans-4-stilbene methanol (t-StM). The structures, chemical composition and
chiroptical activity of the monomers and the copolymers were characterized by
spectral analysis (FTIR, 1H (13C)-NMR, 1H,1H-COSY, UV/vis), thermal methods
(TGA, DSC), fluorescence spectroscopy, gel permeation chromatography and
specific rotation measurements. Influence of the optical activity of monomer
and modifier on modified copolymers suggested a good correlation between the
experimental data obtained (23[?]589=+12.5? for AcLeu and MAcPU-co-AcLeu,
23[?]589=0?+27.5? for (MAcPU-co-AcLeu)-R/S-CSA, 23[?]589=+25? for
(MAcPU-co-AcLeu)-R-EBA, and 23[?]589 = 0? for (MAcPU-co-AcLeu)-St). In
addition, the photobehavior of the stilbene copolymer (MAcPU-co-AcLeu)-St in
film was investigated by UV-vis spectroscopy. The fluorescence quenching of
the stilbene species in the presence of aliphatic/aromatic amine in DMF
solution was evaluated, more efficiently being 4,4??dipyridyl (detection
limit: 7.2 x 10-6 mol/L).
Ocular findings in the chronic renal failure
Authors: Dahal P , Gouli S
Published: July 2015

BACKGROUND The aim of the study was to evaluate the ocular signs in chronic renal failure (CRF) in diabetes and hypertensive patients. MATERIALS AND METHODS Two hundred and thirty eight cases were enrolled in the study from the nephrology unit of College Of Medical Science, Bharatpur, Nepal and examined in the department of Ophthalmology. The study duration was carried out over 2 years from January 2011 to December 2012. RESULT The number of cases in each grade of CRF were mild 80 (26.67%), moderate 84 (28%), severe 75 (25%), end stage renal disease 61 (20.33%). In all the groups the commonest cause of CRF were Hypertension (HTN) 123 out of 300(41%) and diabetes 98(32.67%). The commonest ocular symptoms in CRF was blurring of vision 68%. CONCLUSION Many important ocular findings like vitreous haemorrage, retinal detachment, neovascular glaucoma and cataract are the presentation in chronic renal failure, which can cause marked vision loss. Hence proper awareness should be provided to the people in time to prevent these ocular complications.DOI: http://dx.doi.org/10.3126/jcmsn.v10i2.12949 Journal of College of Medical Sciences-Nepal, 2014, Vol.10(2); 18-26
Densely calcified tuberculous constrictive pericarditis with concurrent active pulmonary tuberculosis infection
Authors: Laudari S , Dhungel S , Gautam S , Dubey L , Prasad G , Bhattacharya R , Subramanyam G
Published: July 2015

Though pulmonary tuberculosis is a common chronic infection in the developing countries like Nepal, the incidence of tubercular constrictive pericarditis is very low. Here we report a patient of active pulmonary tuberculosis with sputum positive for acid fast bacilli along with densely calcified constrictive pericarditis which has been reported as a very rare presentation in the literature.DOI: http://dx.doi.org/10.3126/jcmsn.v10i2.12955 Journal of College of Medical Sciences-Nepal, 2014, Vol.10(2); 41-43
Status of glucose metabolism including insulin resistance and beta cell function in overtly iron loaded Thalassemia patients
Authors: Pan A , Nag SS , Mondal BC , Anindya Dasgupta A , Piyali Mitra P
Published: July 2015

BACKGROUND Abnormality of glucose metabolism is a frequent complication in Thalassemia patients. Both insulin deficiency and insulin resistance has been proposed in its pathogenesis. Some form of abnormality in glucose metabolism is expected at an earlier age in these patients in developing countries like India and Nepal where iron overload is excessive due to lack of chelation therapy.MATERIALS AND METHODS Fasting serum glucose and fasting serum insulin (FSI) were measured in 40 beta-thalassemia major patients, 40 Ebeta- thalassemia patients and 40 controls, all aged between 5 and 12 years. 2 hours after an appropriate dose of oral glucose feed (Children ingested 1.75 g/kg body weight maximum 75 gram dissolved in 250 to 300 ml water) blood samples were drawn again to measure post prandial serum glucose. Iron overload was assessed by measuring liver size, spleen size, total amount of packed cells transfused and serum ferritin. Insulin resistance (IR), insulin sensitivity (%S) and beta cell functions (%B) were derived from the measured laboratory parameters using the latest version of Homeostatic Model Assessment (HOMA) calculator software.RESULTS No one had impaired glucose metabolism or diabetes mellitus beta-thalassemia major patients showed evidence of insulin resistance in the form of significantly higher fasting serum insulin (p value 0.002), IR (p value 0.003), %B (p value 0.017) and significantly lower %S (0.002) when compared with controls. FSI showed positive correlation with total amount of packed cells received (r=0.372, p=0.018), serum ferritin (r=0.345, p=0.029) and spleen size (r=0.427, p=0.006). Similarly, IR also showed positive correlation with total amount of packed cells received (r=0.388, p=0.013), serum ferritin (r=0.336, p=0.034) and spleen size (r=0.425, p=0.005). %S showed negative correlation with all these parameters. %B didn’t show any statistically significant correlation with these parameters.Ebeta- thalassemia patients didn’t have any statistically significant difference in FSI, IR, %S and %B than controls.CONCLUSION Insulin resistance develops as the earliest abnormality in glucose metabolism in overtly iron loaded beta thalassemia major patients at an early age. Ebeta- thalassemia patients with milder phenotype do not develop dysfunction of glucose metabolism at such an early age.Journal of College of Medical Sciences-Nepal, 2014, Vol-10, No-3, 29-36
The Role of Rhamnolipids in Coffee Ring Deposition and Influence of Metal Ions
Authors: Raza Zulfiqar Ali
Published: July 2015

The deposition of material at the edge of an evaporating droplet is known as the coffee ring effect. This phenomenon is widespread in various colloidal and bacterial systems. The study has examined the self-assembly and deposition of colloidal rhamnolipid (a natural surfactant) structures on a glass surface. The effects of the rhamnolipid concentration, pH and the addition of cations on the deposition formation and the alteration in coffee ring effect were studied by using in-vitro scanning electron microscope observation. Above the critical micelle concentration, a transition from ring-like deposition to dispersed deposition is observed. Whereas upon the addition of cations, the multi-distribution of aggregates size enhances the non-homogeneity of the drying film and consequently results in multi-nucleation of rhamnolipid aggregates.
Random Copolymer as Polymeric Surfactant in Seed Emulsion Polymerization
Authors: Yan Xiuhua , Xu Wei , Shao Rong , Tang Lanqin , Shi Wenyan
Published: July 2015

An amphiphilic random copolymer was synthesized and applied as a surfactant in seed emulsion polymerization. The composition and structure of the copolymer were confirmed by Fourier transforms infrared spectroscopy (FTIR), 1H nuclear magnetic resonance spectroscopy (1H NMR), gel permeation chromatography (GPC) and differential scanning calorimetry (DSC). The effect of the copolymer content on the properties of latexes and their sizing properties was discussed. The average size, size distribution and stability of latexes were measured by quasi-elastic light scattering. The results suggest that the copolymer was a random copolymer, and displayed surface-active properties in water. The copolymer content affected strongly the properties of latex and its sizing performance. Monodisperse and nano-sized latex particles were obtained in the presence of 10.5 % copolymer. The thermal characteristics of latex films could be regulated by controlling the content of the copolymer. Adding an appropriate amount of the copolymer could reduce the surface tension of the latexes and promote their adsorption on the paper surface. Latex-treated paper showed a better water resistance and higher surface strength.
On Algorithmic Equivalence of Instruction Sequences for Computing Bit String Functions
Authors: Bergstra J.A. , Middelburg C.A.
Published: July 2015

Every partial function from bit strings of a given length to bit strings of a possibly different given length can be computed by a finite instruction sequence that contains only instructions to set and get the content of Boolean registers, forward jump instructions, and a termination instruction. We look for an equivalence relation on instruction sequences of this kind that captures to a reasonable degree the intuitive notion that two instruction sequences express the same algorithm.
Historical-Critical Knowledge and Restoration Projects in Architecture: the Case of St John the Baptist in Castelvecchio Calvisio (L’Aquila, Italy)
Authors: Malandra Barbara
Published: July 2015

Every action carried out on a historical building should be based on appropriately informed assumptions, as much with respect to the specific architectural and construction features of the building as to its state of preservation. The case of the church of St John the Baptist illustrates how critical examination of the architecture can suggest (even in the absence of urgent problems) methods of intervention that promote the use of cultural heritage, and at the same time improve conditions for conservation of the building’s masonry and any artworks therein. Historical-critical study conducted on the basis of direct investigation of the church’s structures and its archives restores a historical image which, in many respects but not in all, is to be considered completed from a formal point of view. Having survived invasive (and destructive) interventions during the mid-twentieth century, and subsequent restoration in the late 1990s, the church has some unresolved formal, functional, and conservation issues, the reconciliation of which suggest a preliminary proposal to be drawn on the basis of targeted inspections.
Effects of paeonol on the expression of NF-κB pathways in human umbilical veins endothelial cells induced by homocysteine
Authors: Xu Qian , Cao Kai , Xiao Yan-Hong , Du Chao , Dong Xian-Hui , Wang Yu , Zhou Xiao-Hui
Published: July 2015

The aim of this study was to investigate the effects of paeonol on the expression of NF-κB pathway induced by homocysteine. After Human umbilical vein endothelial cells exposed to homocysteine for 24 hours,  paeonol (0.15-0.6 mmol/L) improved the cell viability (p<0.05). NF-κB p65 mRNA expression was reduced largely (p<0.05) and IκB-α protein expression increased significantly (p<0.01). The staining of NF-κB p65 in nucleus was not as much as those in homocysteine injured model group (p<0.01). Therefore, paeonol can inhibit IκB-α protein degradation and suppress NF-κB transferred into nuclear in order to inhibit the activation of NF-κB.

 
Antidiarrheal and antispasmodic activities of Polygonum bistorta rhizomes are mediated predominantly through K+ channels activation
Authors: Ali Muhammad Zeeshan , Janbaz Khalid Hussain , Mehmood Malik Hassan , Gilani Anwar Hassan
Published: July 2015

Polygonum bistorta is a popular medicinal herb used to treat diarrhea. This study provides pharmacological basis to its folk use in diarrhea using in vivo and in vitro assays. Administration of P. bistorta  rhizomes extract to mice offered protection against castor oil-induced diarrhea at 300-1,000 mg/kg and was found safe up to the dose of 5 g/kg. In isolated rabbit jejunum, the extract caused a dose-dependent relaxation of spontaneous and low K+ (25 mM)-induced contractions with weak effect against high K+ (80 mM). In tissues pretreated with glibenclamide or tetraethylammonium chloride (TEA), the relaxant effect of the extract was markedly inhibited by TEA only. While verapamil showed complete relaxation of spontaneous, low K+, low K+ with TEA and high K+-induced contractions. In guinea-pig ileum, mild atropine-sensitive effect was observed. This study indicates that P. bistorta possesses anti-diarrheal and antispasmodic activities mediated predominantly through K+-channels activation along with weak Ca++ antagonist effect.

 
Solving the (n2 − 1)-Puzzle with 8/3 n3 Expected Moves
Authors: Parberry Ian
Published: July 2015

It is shown that the greedy algorithm for the \((n^2-1)\)-puzzle makes \(\tfrac{8}{3}n^3 +O(n^2)\) expected moves. This analysis is verified experimentally on 10,000 random instances each of the \((n^2-1)\)-puzzle for \(4 \leq n \leq 200\).
Turbulence Modeling of Flows with Extensive Crossflow Separation
Authors: Panaras Argyris
Published: July 2015

The reasons for the difficulty in simulating accurately strong 3-D shock wave/turbulent boundary layer interactions (SBLIs) and high-alpha flows with classical turbulence models are investigated. These flows are characterized by the appearance of strong crossflow separation. In view of recent additional evidence, a previously published flow analysis, which attributes the poor performance of classical turbulence models to the observed laminarization of the separation domain, is reexamined. According to this analysis, the longitudinal vortices into which the separated boundary layer rolls up in this type of separated flow, transfer external inviscid air into the part of the separation adjacent to the wall, decreasing its turbulence. It is demonstrated that linear models based on the Boussinesq equation provide solutions of moderate accuracy, while non-linear ones and others that consider the particular structure of the flow are more efficient. Published and new Reynolds Averaged Navier–Stokes (RANS) simulations are reviewed, as well as results from a recent Large Eddy Simulation (LES) study, which indicate that in calculations characterized by sufficient accuracy the turbulent kinetic energy of the reverse flow inside the separation vortices is very low, i.e., the flow is almost laminar there.
The Occurrence and Toxicity of Indospicine to Grazing Animals
Authors: Fletcher Mary , Al Jassim Rafat , Cawdell-Smith A.
Published: July 2015

Indospicine is a non-proteinogenic amino acid which occurs in Indigofera species with widespread prevalence in grazing pastures across tropical Africa, Asia, Australia, and the Americas. It accumulates in the tissues of grazing livestock after ingestion of Indigofera. It is a competitive inhibitor of arginase and causes both liver degeneration and abortion. Indospicine hepatoxicity occurs universally across animal species but the degree varies considerably between species, with dogs being particularly sensitive. The magnitude of canine sensitivity is such that ingestion of naturally indospicine-contaminated horse and camel meat has caused secondary poisoning of dogs, raising significant industry concern. Indospicine impacts on the health and production of grazing animals per se has been less widely documented. Livestock grazing Indigofera have a chronic and cumulative exposure to this toxin, with such exposure experimentally shown to induce both hepatotoxicity and embryo-lethal effects in cattle and sheep. In extensive pasture systems, where animals are not closely monitored, the resultant toxicosis may well occur after prolonged exposure but either be undetected, or even if detected not be attributable to a particular cause. Indospicine should be considered as a possible cause of animal poor performance, particularly reduced weight gain or reproductive losses, in pastures where Indigofera are prevalent.
Pre-Clinical Intravenous Serum Pharmacokinetics of Albumin Binding and Non-Half-Life Extended Nanobodies®
Authors: Hoefman Sven , Ottevaere Ingrid , Baumeister Judith , Sargentini-Maier Maria
Published: July 2015

Nanobodies are antigen-binding, single variable domain proteins derived from naturally-occurring, heavy chain only antibodies. They are highly soluble, stable, and can be linked to build multi-specific formats. Several Nanobodies are currently in clinical development in different therapeutic areas, for both chronic and acute applications. For the former, prolonged exposure is achieved by half-life extending moieties that target endogenous albumin, while for the latter, non-half-life extended constructs are preferable. To demonstrate the general pharmacokinetic behavior of both formats, serum levels of seven intravenously administered Nanobodies were analyzed in cynomolgus monkeys, mice or rabbits. In monkeys, the total clearance of a monomeric irrelevant Nanobody was rapid (2.0 mL/(min*kg)) and approximated the species glomerular filtration rate, indirectly suggesting that the Nanobody was mainly eliminated via the kidneys. When linked to an anti-albumin Nanobody, a 376-fold decrease in clearance was observed, resulting in a terminal half-life of 4.9 days, corresponding to the expected species albumin half-life. Similar conclusions were drawn for (non-) half-life extended mono-, bi- and trimeric Nanobodies in mice or rabbits, suggesting that these kinetic principles apply across species. Applying this knowledge to species translation and study design is crucial for successful pre-clinical development of novel therapeutic Nanobody candidates.
Model-Based Comparison of Antibody Dimerization in Continuous and Batch-Wise Downstream Processing
Authors: Sellberg Anton , Ojala Frida , Nilsson Bernt
Published: July 2015

Monoclonal antibodies are generally produced using a generic platform approach in which several chromatographic separations assure high purity of the product. Dimerization can occur during the fermentation stage and may occur also during the downstream processing. We present here simulations in which a traditional platform approach that consist of protein A capture, followed by cation-exchange and anion-exchange chromatography for polishing is compared to a continuous platform in which dimer removal and virus inactivation are carried out on a size-exclusion column. A dimerization model that takes pH, salt concentration and the concentration of antibodies into account is combined with chromatographic models, to be able to predicted both the separation and the degree to which dimers are formed. Purification of a feed composition that contained 1% by weight of dimer and a total antibody concentration of 1 g/L was modeled using both approaches, and the amount of antibodies in the continuous platform was at least 4 times lower than in the traditional platform. The total processing time was also lower, as the cation-exchange polish could be omitted.