bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling the Forces Induced by the Two-Phase Flow on Deep Water Production Risers
Authors: Bordalo Sergio N. , Morooka Celso K. , Oliveira Alessandro P.
Published: May 2015

This paper points out the influence of the internal flow of two-phase oil and gas mixtures on the motion of slender risers hanging from floating production units in curved configurations (for instance, catenary risers) used for offshore petroleum production in deep waters. The internal flow mass and momentum may impose a natural whipping displacement adding to the concerns of stress and fatigue. Usually, the internal flow may display different two-phase patterns (bubble, slug, churn, annular or stratified mixtures) possessing completely different characteristics; in the case of slugs, their intemittency may induce an oscillatory movement on the suspended pipeline. The fluid dynamic forces depend on the flow rates of both oil and gas phases, requiring the simulation of the pipeline movement under production conditions. In this paper, a modeling of induced forces caused by the internal two-phase slug flow is described, and results from numerical simulations are presented for a steel catenary riser configuration, showing the importance of the internal flow forces on the movements of a production riser.
Improving Flow Stability and Increase of Oil Production in Electrical Submersible Pump Systems Through Demulsifier Application in Jubarte Field
Authors: dos Santos A. W. , Borges O. C. , Cristante V. M. , Nokai R. A. , Furtado R. G.
Published: May 2015

In recent past, most of Brazil's oil production was generated from siliciclastic reservoirs in scenarios of deep and ultra-deep water of the Campos Basin, being much effort focused on developing technologies to guarantee production optimization. Despite the great experience acquired by Petrobras in evaluating dynamic behavior of deepwater fields, new production scenarios of heavy oil reservoirs are even more challenging due to their high oil viscosity that generates emulsion stability.

Jubarte field (siliciclastic turbidite reservoir) development features 15 heavy oil producing wells tied to P-57 floating production storage and offloading (FPSO) vessel. Each well is equipped with a 1500HP electrical submersible pump (ESP) installed in a caisson located 210 meters away from the wellhead in water depths varying from 1260 to 1360m. Over the last 3 years, since Jubarte first oil, the maturity curve of the wells has revealed a scenario where ESP has been recognized as a critical component of the subsea production system to sustain well production.

Normally adopted in projects to anticipate production during the early years, ESPs in Jubarte field have been presenting an outstanding performance, overcoming oil viscosity limitations or unpredictable multiphase flow regime with strong emulsion formation (both tied to injection of viscosity reducers and the advent of natural free water from the reservoir).

Operating ESPs installed at the seabed poses challenges in many aspects. Understanding the flow pattern (to ensure effective startup and run in optimal conditions), pump and caisson fluid dynamic behavior (to allow the pump ride through some observed inflow discontinuities) are two essential issues.

This work aims to introduce the phenomenon of flow intermittency experienced during the operation of ESPs installed in vertical caissons in Jubarte field. It also demonstrates the engineering approach and the main proposed solutions to overcome the problem of well instability. The advantages obtained through the injection of demulsifier upstream the ESP are finally presented as a key element to promote stability, allowing ESP to run properly with significant gains in production rate.
Innovative Drilling Technologies Contribute in Implementing New Gas Lift Well Design on Statfjord Field, North Sea
Authors: Lunkad Siddhartha F. , Grindhaug Gaute , Hussain Sajjad , Walker Daryl , Dhaher Karam Sulaiman
Published: May 2015

Statfjord Field is one of the largest and oldest fields on NCS (North Sea Continental Shelf) and operates with three platforms Stafjord A, B and C. In recent years, slot recovery to drill more wells has posed big challenges to deliver wells with Gas Lift design due to extensive and cost/time consuming P&A and casing cut and pull operations. In addition to these technical challenges, improving operational excellence has driven the concept of innovative casing design with 11 ¾-in liner. This design eliminates the time spent on extensive casing retrieval operations. This reduces time and risks associated with drilling 17 ½-in section that requires changing from 13 5/8-in to 21 ¼-in BOP, higher flow rates for hole cleaning, larger volume of cutting injection, and waiting 13 3/8-in casing hangers that are crucial long lead items. Installation of 11 ¾-in liner at required depth and cementing, potential collapse of Hordaland formation due to extended time exposure, high flow rates for hole cleaning and minimizing well collision risks with producers in 8 ½-in were identified as high priority design goals in the early planning phase. To address aforementioned challenges and meet design goal in time and cost efficient way, innovative ideas were fundamental necessity. This paper discusses the integration of novel drilling approaches used in accomplishing a new gas lift well design that has opened redundant well slotson Statfjord field for drilling. Operational highlights leading to successful well delivery are:

First use of dual reamer RSS BHA in 12 ¼ x 13 ½-in to minimize the rat hole and exposure time across “creeping” Hordaland formation in one run and helped 11 ¾-in liner to reach gas lift formation strength depth. Use of new generation RSS technology to drill ~930m 8 ½-in section to widen the operational flow range for hole cleaning and steering in high stick slip and collision environment. Use of modern surveying technique and magnetic ranging technology to drill 8 ½ -in section in potential collision environment.

This was first ever use of dual reamer point the bit RSS BHA in North Sea and New generation RSS and special surveying technique on Statfjord.
Design and Application of Multiphase Sucker-Rod Pumps in Wells with High Gas-Oil Ratios
Authors: Wang Haiwen , Zheng Sixu , Yang Daoyong
Published: May 2015

A robust and pragmatic technique has been developed to design and apply a multiphase sucker-rod pump in wells with high gas-oil ratios. More specifically, the pump structure has been designed according to its working mechanisms in the presence of high gas-oil ratios and various liquid contents. Effective solutions of enforcing gas evacuation while enhancing oil production have also been made possible. In particular, a unique gas buffer is designed to include two chambers (i.e., a gas chamber and a fluid chamber) inside which are connected through the slotted liner, enforcing gas evacuation while preventing the pump from gas lock. Also, such designed gas buffer can be bypassed when the stroke is shortened, functioning as the traditional downhole pump. It has been found from field applications that average pumpingefficiency can be increased up to 16.6% by using such designed multiphase sucker-rod pumps in wells with high gas-oil ratios where conventional pumps have found their limits.
Gas Effect in ESP System Stage by Stage Analysis
Authors: Oliva G. B. , Galvão H. L. , dos Santos D. P. , Maitelli A. L. , Costa R. O. , Maitelli C. W.
Published: May 2015

One of the main problems regarding the use of artificial lift method by Electric Submersible Pump (ESP) systems is the presence of gas in the pump. This paper presents and describes an analysis of ESP systems using a stage by stage calculation to determine intake and discharge pressures to adjust total dynamic head (TDH) for each stage of the pump.

The modeling was designed acknowledging free gas in the pump and iterative calculations are applied to recalculate, for each stage, fluid characteristics and physical properties, such as viscosity, density, formation volume factor, surface tension, solubility ratio, oil-gas ratio (OGR), and other flow characteristics along the tubing, like temperature and pressure. Developed modeling validation was achieved by comparisons in two scenarios. In the first one, fixed values of intake pressure and changeable values of GOR were used to assess gas effect. In the tests for the second scenario, fixed values of OGR and changeable values of intake pressure were used.

Necessary research was done through a developed computational tool used to size ESP components. The results were different from those obtained with usual calculations and it may be implied that the developed modeling is more accurate to determine parameters related to this artificial method. Also, the results were more consistent and closer to the actual behavior of multiphase flow phenomena within the tubing because each stage has its characteristics individually evaluated. These observations may have effect on the number of pump stages and influence in choosing the adequate equipment of the system.
Development of Affordable High-Temperature Downhole Sensors
Authors: Muñoz Heber , Bruni Marcelo , Mazzola Ricardo , Colla Miguel , Mosquera Manuel Tapia , Teves Ricardo , Oyarzun Raul
Published: May 2015

Conventional technology on downhole sensors allowed the development of standard equipment capable to work in wells up to 150°C and some cases 175°C permanently. If higher temperature is required, existing technology offers sensors that can operate up to 260°C without electronics downhole. Such sensors use separate encased multicore cables. But cost and deployment are limitations making instrumentation not feasible for high WC wells. Thus, confining these products to specific application such SAGD.

Using Defense and Aerospace technology, an affordable downhole sensor was developed for Panamerican Energy to withstand 225°C permanently and have excursions on 250°C. This sensor does not require an additional cable. Communication is achieved by over imposing the digital signal in the existing power cable, reducing cost and installation complexity. This paper shows the development of the product, specifications, and lab tests, field examples that helped to maximize production and protect the artificial lift equipment.
Implementation of the Technique Auto Gas Lift in Field Corvina Block Z-1, Peru Offshore
Authors: Matos Yrael , Saire Jorge , Vargas Claudia
Published: May 2015

The Corvina field is located to the north-west of Peru, in Tumbes Basin, Block Z1 (Offshore Perú), Figure 1. The reservoir, Zorritos Oil is defined as an anticlinal structure of fine- to medium-grained sandstone. The Field begins its exploitation in 2007 by 21XD well completion and it was not until late 2010 when the commerciality of the field was declared. The wells produced by natural flow of non-selective completions. The dominant reservoir mechanism drive is solution gas, with an initial pressure of 3300 psi, bubble pressure of 2850 psi and an estimated current static pressure of 2450 psi. To date 13 wells have been drilled between delineation and development wells, two wells have dual completion to meet functions as a producer and injector, an injector and the remaining wells are producers.

Production behavior of the field, production logging (PLT / MPLT) in existing wells and electrical logging in new wells confirm the formation of a secondary gas cap of higher pressure at the top of the reservoir, due to the effect of being the reservoir below the bubble pressure and gas injection through injection wells in these sands, this began from late 2011. The production behavior of wells shows a low lift efficiency of oil along tubing, due producing in conjunction with high volumes of gas and back-pressure on wellhead.

The workover campaign in 2012 was performed in order to select gas and oil producing sands, and install an “Auto Gas Lift” (AGL) installation, in the gas cap by including in the mechanical completion conventional gas Lift equipment, this permitted optimizing the production of gas and increased oil production.

For design of an installation, a commercial software was used to calculate the size of the injection port, so that allow the passage of required gas volume according to the well flow dynamics derived from nodal analysis.

The application of the technique of AGL in Corvina has been successful, achieving an increase in production wells, noting that one of them was up to 300 BOPD. These results have allowed expanding this technique to other fields of block Z-1, with positive results.
Alternatives to Avoid High Human Efforts in Progressing Cavity Pump Operations
Authors: Magnoni Pablo J , Pich Pablo J
Published: May 2015

Alternatives to Avoid High Human Efforts in Progressive Cavity Pump Operations

The next opportunities for improvement were identified for operations of Progressive Cavity Pump (PCP) systems, which have caused lost time, injury to people, and damage to equipment:

Make-up and disassembling of PCP bottom hole assemblies at field or workshop, where mostly is absolutely necessary to use hand tools, and those activities require a high human effort. Besides, the personnel use extension tubes (snipes) connected to the pipe wrenches, although that is not technically and safety recommended. Installation and removal of surface equipment, even inside of well location. This operation is commonly performed using rig's auxiliary lifting mechanism (winch), and the loads are driven manually with a rope. In those cases, people have to do high efforts and loss control of the load movement.

Hydraulic tools can be used for both situations, but these are not always available, are expensive, require skilled labor, are not manually transportable, and in some situations there is not enough space for their operation (cranes).

The objective of this study is to find practical and inexpensive alternatives to perform the above operations in reliable and safe way, using tools that can be operated and transported by only one person. The following aspects were considered:

Argentina PCP Experience, in field and workshop operations. Incident Investigations. Mechanical Analysis of forces and displacements involved. International standards. Ergonomic studies.

The goals were achieved through the implementation of the following alternatives:

Use of hand wrenches (friction or chain style), combined with torque multiplier and torque wrenches, detecting that also applies to reciprocating rod pump assemblies. Use of the rig's lifting mechanisms, main (traveling hoist) and secondary (winch), combined with a mobile sheave mounted on the equipment to transport, and using a fixed point available on location as retention line.

We expect with development and communication of this work, contribute to the reduction of incidents that can damage people and equipment, as well as improving the operations efficiency.
Chloramine: An Effective Biocide for Produced Waters
Authors: Boal Andrew K. , Mowery Charles
Published: May 2015

Produced waters containing high levels of oxidant demanding chemicals such as ammonia, hydrogen sulfide, and iron are often thought to be difficult to disinfect using oxidizing biocides such as hypochlorite. It is the goal of this paper to present evidence that chloramines generated in situ through the reaction of native ammonia present in produced water with hypochlorite added as a disinfectant can effectively control microbial populations in produced water. Testing was accomplished by treating produced waters being held in retention ponds with a hypochlorite-based disinfectant solution produced at the pond location using a mobile on-site generation (OSG) system. OSG in this treatment scenario involves the electrolysis of sodium chloride brines to yield a hypochlorite-based oxidizing biocide solution. This solution is then injected into the produced water at a rate to ensure that the Oxidation-Reduction Potential (ORP) of the treated water is ~450 mV. Samples of both the raw and treated water were analyzed for both chemical composition as well as microbial populations. Raw water in this study was found to consistently have relatively high ammonia content in the range of 58 to 120 mg/L along with an ORP in the range of −228 to 190 mV. Populations of Acid Producing Bacteria (APB) and Sulfate Reducing Bacteria (SRB) were found to be 1010 and 1011 MPN/mL, respectively. On site analysis of the treated water fond that the ORP after oxidant injection was between 464-543 mV, a value consistent with the presence of chloramines and not free chlorine. Populations of APBs and SRBs in the treated water were found to be 1 and 10 MPN/mL, respectively, representing a 10 log reduction in the resident bacteria population of these waters. Overall, this data clearly demonstrates that chloramines generated in situ through the treatment of high ammonia waters with OSG produced hypochlorite can effectively control the populations of key microbes in produced waters. Effectively controlling microbial populations using in situ generated chloramines offers the ability to achieve required disinfection of produced waters with hypochlorite based biocides without meeting the total chlorine demand of the water being treated.
Design and Installation of a Water Management Infrastructure for Newfield Exploration Company's Cana Woodford Shale Play
Authors: Tipton D. Steven
Published: May 2015

Water is the most common and heavily used fluid in the petroleum industry. It is produced along with oil and gas from nearly every well. Fresh water is used as a base fluid in production, drilling and completion operations. Produced water is primarily handled in three ways: as a base fluid in hydraulic fracturing, for pressure maintenance in secondary or tertiary recovery projects, or for disposal into salt-water injection wells.

Hydraulic fracturing uses more water than any other process in the drilling and completion of unconventional wells. An easy way to think of the need for water is: No water, No fracturing, No oil or gas resource play. This paper's focus is on how Newfield Exploration Company approached the design and installation of an infrastructure system for the procurement, transportation, storage, reuse and disposal of water for hydraulic fracturing and associated operations in its Cana Woodford Shale Play.

Newfield's Cana Woodford Shale Play covers over 275,000 net acres in central Oklahoma running from Elmore City in the southeast to Watonga in the northwest. When Newfield started on its new venture in the Cana Woodford, the existing infrastructure in the area was not capable of supporting its planned drilling and completion program nor the resulting production and water disposal requirements. To accommodate the exploratory drilling and completion plan, Newfield would install discrete water management systems for each well, which would include (1) sourcing water, (2) constructing frac pits, (3) transporting water to the storage pits in sufficient quantity, and (4) transferring water from the storage pits to well location to support the completions.

These one-well water management systems were a necessity for the exploratory drilling program; however, as Newfield shifted to infill drilling and field development, it sought to install a more efficient, fully integrated water management infrastructure that would reduce trucking, make more efficient use of storage space for water, provide broader access to geographically dispersed water resources, and allow for the recycling of produced water as a hydraulic fracturing fluid.

Newfield forged new relationships with landowners as a part of establishing operations in the region. Landowner agreements were required to construct pads, obtain right-of-ways to lay water transport pipelines, and build frac pits and other facilities. Several landowners were instrumental in helping our water management team identify water sources in the Cana Woodford play especially in light of the ongoing drought in Oklahoma.
Improving Flotation Methods to Treat EOR Polymer Rich Produced Water
Authors: Richerand Frank , Peymani Yoosef
Published: May 2015

Flotation units, which operate with the assistance of gas in the flotation process, have been widely used for the treatment of produced water both onshore and offshore. Differing technologies are applied to Flotation units for a specific application. The advantages and disadvantages of each arrangement plus the requirements of the process determine the choice of gas floatation mechanism. These methods can be divided in two major categories: Induced Gas Floatation (IGF), Dissolved Gas Floatation (DGF). A close comparison of IGF and DGF is studied in this paper to identify the main criteria affecting the performance and functionality of floatation units and their accessories in different environments. Additionally, this paper will describe the effects and benefits of using both IGF and DGF at the same time. The authors will verify their hypothesis through three years of laboratory and field study.
Ten Years Back, Five Years Forward: The Data Seal of Approval
Authors: Dillo Ingrid , De Leeuw Lisa
Published: May 2015

If we want to share data, the long-term storage of those data in a trustworthy digital archive is an essential condition. Trust is the basis of storing and sharing data. That trust must be present in the various stakeholders involved. Certification of digital archives can make an important contribution to the confidence of these stakeholders in the digital archives.Ten years ago DANS was assigned the task of developing a Seal of Approval for digital data to ensure that archived data can still be found, understood and used in the future. In 2009 this Data Seal of Approval (DSA) was transferred to an international body, the DSA Board, which has managed and further developed the guidelines and the peer review process ever since.The objectives of the DSA are to safeguard data, ensure high quality and guide reliable management of data for the future without requiring implementation of new standards, regulations or heavy investments. The DSA contains 16 guidelines for applying and verifying quality aspects concerning the creation, storage, use and reuse of digital data.Based on feedback from data archives that applied for a DSA and different case studies we have gained some insight into the benefits of DSA. Still, the impact of having the Seal is not easy to measure. Seal holders usually refer to qualitative benefits in the form of increased awareness of the value of their repositories to their communities, funders and publishers.Ten years down the line we can safely state that the Data Seal of Approval has proven its added value. If we try to look five years into the future, what can we expect? There are different developments: a growing interest in DSA among European research infrastructures, the collaboration between DSA and the ISCU World Data System under the umbrella of the RDA (Research Data Alliance) and the European Commission is showing a growing interest in certification services.The success of DSA also provides the challenge to further professionalize the DSA organization in the coming years, this to enable its community to continue to grow. All in all there are promising developments for a bright future for the Data Seal of Approval.
Essentials for Data Support: Training the Front Office
Authors: Grootveld Marjan , Verbakel Ellen
Published: May 2015

At the end of 2011 a Data Intelligence 4 Librarians course was developed to provide online resources and training for digital preservation practitioners, specifically library staff. Lessons learned during the first rounds of the course and developments in the Research Data Management landscape have led to a revision of the positioning, the structure and the content of the course. This paper describes both the three main drivers for the revision, the changes themselves and the lessons that can be drawn from them, after three training rounds in 2014 in the revised format under the new programmatic title of Essentials 4 Data Support.
Enhancing side illumination of plastic optical fiber by using TiO2 particles and CO2 laser
Authors: Huang Juan , Křemenáková Dana , Militký Jiří , Wiener Jakub
Published: May 2015

Plastic optical fiber (POF) is highly appreciated for its applications in glowing textiles. However, fabricating thin POF with good side illuminating effect is a challenge due to the complicated manufacturing processes. CO2 laser treatment is normally applied to enhance the surface roughness without significant influence on other properties of materials. Titanium dioxide (TiO2) is widely studied for its high photo activity and thermal stability. The surface modification combined with TiO2 particles and CO2 laser treatment was carried out to investigate the side illuminating effect of POF. The images of surface morphology show that TiO2 particles reduce the thermal damage of POF surface during CO2 laser treatment. The results from side illumination testing prove that the employment of TiO2 particles, combined with CO2 laser treatment, could enhance the side illumination of POF for longer lasting application. Cyclic CO2 laser treatment can decrease the heat accumulation in POF and may have adverse effect on side illumination. The investigation of tensile testing indicates that only the strain value is more influenced by laser treatment due to the brittleness and low thermal stability of POF material.
Study of process window development for high deposition-rate laser material deposition by using mixed processing parameters
Authors: Zhong Chongliang , Gasser Andres , Kittel Jochen , Schopphoven Thomas , Pirch Norbert , Fu Jinbao , Poprawe Reinhart
Published: May 2015

For several years, the interest in additive manufacturing is continuously expanding, owing to the paradigm shift that new production processes, such as laser material deposition (LMD), provide over conventional manufacturing technologies. With LMD, three-dimensional, complex components out of a wide range of materials can be manufactured consecutively layer-by-layer. However, aiming for the production of large components with LMD, the currently achieved deposition-rates of approximately 0.5 kg/h remain a major concern in regards to processing time and economic feasibility. In this respect, an experimental setup for high-deposition rate LMD is built up in the current work. Furthermore, an approach for developing a process window for resource efficient, high-deposition rate LMD is investigated in this paper. For the production of sound layers with LMD, the processing parameters need to be considered in an appropriate relation. Thus, by setting the main processing parameters: powder mass flow, traversal speed, laser power, and laser spot diameter into proportion, the mixed processing parameters: energy mass density and energy area density can be defined. Based on the metallographic investigation of laser deposited Inconel 718 single tracks regarding dilution, aspect ratio of track (ratio of track width to track height) and level of porosity, upper and lower limits for these two parameters can be set which represent process window boundaries. With this approach, a processing parameter field can be defined, to deposit sound Inconel 718 single tracks with a deposition-rate of approximately 5 kg/h and powder capture efficiency higher than 90%.
Flora of springs in the Polish Tatra Mountains – habitat and phytosociological characteristics of crenophiles
Authors: Smieja Agata
Published: May 2015

The flora of 179 springs in Tatra National Park was studied between 2003-2006. These springs represent complete diversity in the region with respect to altitude (from 900 to 1960 m a.s.l.), kind of bedrock (on siliceous and carbonate bedrock) and spring discharge (from 0.1 to >3500 l/s), and they also represent various ecomorphological types (mainly rheo- and helocrenes). In the springs, 239 plant taxa were recorded (60 mosses, 51 liverworts and 128 taxa of vascular plants). Among these species, 13 taxa (Arabis soyeri subsp. subcoriacea, Bryum schleicheri, Cardamine amara, Dichodontium palustre, Epilobium alsinifolium, E. anagallidifolium, Heliosperma quadridentatum, Palustriella commutata, Philonotis calcarea, P. seriata, Rhizomnium magnifolium, Scapania paludosa, S. uliginosa) had an ecological optimum in crenic habitats (crenophiles). Ecological and phytosociological characteristics of these species, as well as their distribution in the investigated springs, were shown.
Asian Sand Dust Increases MUC8 and MUC5B Expressions via TLR4-Dependent ERK2 and p38 MAPK in Human Airway Epithelial Cells
Authors: Choi Yoon Seok , Bae Chang Hoon , Song Si-Youn , Kim Yong-Dae
Published: May 2015

Background

Asian sand dust (ASD) is a natural phenomenon and originates from the deserts of China and is known to contain various chemical and biomolecular components that enhance airway inflammation. The overproduction of airway mucins is an important pathologic finding in inflammatory airway diseases. However, the mechanism of ASD on mucin production of airway epithelial cells has not been elucidated.

Objective

To investigate the effect and signaling pathway of ASD on mucin expressions in human airway epithelial cells.

Methods

In the NCI-H292 cells and the primary cultures of human nasal epithelial cells, the effect and signaling pathway of ASD on MUC8 and MUC5B expressions were investigated using reverse transcriptase-polymerase chain reaction (RT-PCR), real-time PCR, enzyme immunoassay, and immunoblot analysis with several specific inhibitors and small interfering RNA (siRNA).

Results

ASD increased MUC8 and MUC5B expressions and activated the phosphorylations of extracellular signal-regulated kinase 1/2 (ERK1/2) and p38 mitogen-activated protein kinase (MAPK). U0126 (ERK1/2 MAPK inhibitor) and SB203580 (p38 MAPK inhibitor) inhibited ASD-induced MUC8 and MUC5B expressions. In addition, knockdowns of ERK2 and p38 MAPK by siRNA blocked ASD-induced MUC8 and MUC5B mRNA expressions. Toll-like receptor 4 (TLR4) mRNA expression was increased after treatment with ASD. Knockdown of TLR4 by siRNA blocked ASD-induced MUC8 and MUC5B mRNA expressions. Furthermore, the phosphorylations of ERK1/2 and p38 MAPK were blocked by knockdown of TLR4.

Conclusions

These results show that ASD induces MUC8 and MUC5B expressions via TLR4-dependent ERK2 and p38 MAPK signaling pathway in human airway epithelial cells.
The Use of Image-Guidance during Transsphenoidal Pituitary Surgery in the United States
Authors: Chung Thomas K. , Riley Kristen O. , Woodworth Bradford A.
Published: May 2015

Background

Intraoperative image guidance is a useful modality for transsphenoidal pituitary surgery. However, the outcomes associated with this technology have not been systematically evaluated.

Objective

The purpose of the study was to quantify complication rates with and without the use of image guidance during transsphenoidal pituitary surgery using a nationwide database with broadly applicable results.

Methods

A retrospective analysis of the Nationwide Inpatient Sample was performed from 2007 to 2011. Transsphenoidal pituitary resections for adenomas were identified by International Classification of Diseases-9th Revision, Clinical Modification code. The effect of image guidance on cerebrospinal fluid (CSF) leak complications and cost-benefit was analyzed.

Results

A total of 48,848 transsphenoidal pituitary resections were identified, of which 77.5% were partial resections and 22.5% were complete. Pathologic indications included benign (89.3%), malignant primary (0.6%), and malignant secondary (0.4%). Complications included same-stay death (0.4%), CSF leak (8.8%), postoperative CSF rhinorrhea (1.9%), diabetes insipidus (12.4%), and meningitis (0.4%). Image guidance was employed in 7% (n = 3401) of all cases. When analyzed by modality, computed tomography (CT)-assisted procedures had lower CSF rhinorrhea rates (1.1%) compared with cases with no image guidance (1.9%), whereas magnetic resonance (MR)-assisted procedures had the highest rates (2.7%, χ2 p < 0.001). Rates of CSF leak demonstrated a similar pattern (CT 6.4%, no image guidance 8.9%, MR 9.2%, χ2 p < 0.001). CT-assisted surgery had significantly shorter length of stay (2.9 days) versus no image guidance (3.7 days, p < 0.001), lower total charges ($47,589 versus $62,629, p < 0.001), and lower total cost ($16,748 versus $20,530, p < 0.001).

Conclusions

CT-assisted surgery is associated with a lower rate of CSF leak, shorter length of stay, and lower cost compared with patients without image guidance. Further studies that control for severity and extent of disease are warranted to confirm this finding.
Chronic Obstructive Pulmonary Disease Predicts Chronic Rhinosinusitis without Nasal Polyps: A Population-Based Study
Authors: Chien Chen-Yu , Tai Shu-Yu , Wang Ling-Feng , Lee Charles Tzu-Chi
Published: May 2015

Background

Few studies have investigated the relationship between chronic obstructive pulmonary disease (COPD) and chronic rhinosinusitis without nasal polyps (CRSsNP) outcomes. The aim of this study was to investigate the association between COPD and the risk of CRSsNP in a large national sample.

Methods

Patients 15 years or older with a new primary diagnosis of COPD (International Classification of Diseases, Ninth edition [ICD-9], 491, 492, 494, and 496) between 2000 and 2007 were identified from the National Health Insurance Research Database of Taiwan. The patients were compared with sex-, age-, residence-, and insurance premium–matched controls, and both groups were followed up until the end of 2008 for instances of CRSsNP, defined as ICD-9 codes CRS (473, 473.0, 473.1, 473.2, 473.3, 473.8, and 473.9), excluding NP (471, 471.0, 471.1, 471.8, and 471.9). Competing risk-adjusted Cox regression analyses were applied after adjusting for sex, age, residence, insurance premium, steroid use (topical or systemic), hyperlipidemia, diabetes, hypertension, coronary artery disease, hospital admission days, and mortality.

Results

We included 34,029 cases and 34,029 matched controls in this study. Among the 68,058 subjects, 569 developed CRSsNP during a mean (standard deviation [SD]) follow-up period of 5.0 years (SD 2.2 years). COPD was an independent predictor of CRSsNP in the fully adjusted model (hazard ratio = 3.24; 95% CI = 2.65-3.96; p < 0.01).

Conclusion

COPD was associated with an increased risk of CRSsNP in this study population, independent of a number of potential confounding factors.
Teacher Collaboration in Instructional Teams and Student Achievement
Authors: Ronfeldt Matthew , Farmer Susanna Owens , McQueen Kiel , Grissom Jason A.
Published: May 2015

This study draws upon survey and administrative data on over 9,000 teachers in 336 Miami-Dade County public schools over 2 years to investigate the kinds of collaborations that exist in instructional teams across the district and whether these collaborations predict student achievement. While different kinds of teachers and schools report different collaboration quality, we find average collaboration quality is related to student achievement. Teachers and schools that engage in better quality collaboration have better achievement gains in math and reading. Moreover, teachers improve at greater rates when they work in schools with better collaboration quality. These results support policy efforts to improve student achievement by promoting teacher collaboration about instruction in teams.
Heterotrophic activities in eutrophic lake sediment by indigenous bacterium Bacillus firmus
Authors: Karim Md Abdul , Akhter Nazneen , Hoque Sirajul
Published: May 2015

Bacterial isolates, Bacillus firmus (LS-31) were collected from eutrophic Gulshan lake, Dhaka sediments and introduced to stimulate inorganic nutrient regeneration in the laboratory. The bacteria stimulated net regeneration of dissolved inorganic nitrogen and inorganic phosphorus in the water by about two folds at both the incubation temperatures (26°C and 30°C). These results suggest that the application of B. firmus would be promising for the stimulation of inorganic nutrient regeneration at the eutrophic environment.Bangladesh J. Zool. 41(1): 73-78, 2013
Neurofeedback: A non drug treatment of attention deficit/hyperactivity disorder
Authors: Yasmeen BH Nazma
Published: May 2015

Abstract not availableNorthern International Medical College Journal Vol.6(2) 2015: 43-44
Physicianpatient communication : a tool for optimum satisfaction
Authors: Talukder Abu Mohammad , Mahejabin Farzana , Faruk Abdullah Al , Sultan Quazi Rakibus , Sufian Abu , Mannan Md Abdul
Published: May 2015

Abstract not availableNorthern International Medical College Journal Vol.6(2) 2015: 48-49
Immediate outcome of neonates with maternal hypertensive disorder of pregnancy at a neonatal intensive care unit
Authors: Hassan Mahmuda , Begum Marium , Haque SM Zabrul , Jahan Nasim , Yasmeen BH Nazma , Mannan Abdul , Choudhury Kona , Rahman Hamidur
Published: May 2015

Aims : Hypertensive disorders in pregnancy remain a major cause of maternal and neonatal morbidity and mortality worldwide. This study prospectively examined the immediate neonatal outcome of women with maternal hypertensive disorder of pregnancy( HDP).Methods : Sixty mothers and their newborn were selected. Mothers with gestational hypertension, preeclampsia, preeclampsia superimposed on chronic hypertension and chronic hypertension were included.Results : Forty five (75%) mothers were mutipara and 15(25%) were primipara. Mean maternal age was 26.4 years. Mean gestational age was 34+4 weeks. 38 were male and 22 were female with Male: Female ratio was 1.72: 1. Thirty six (60%) were from in patient with regular antenatal check up, 60% mothers had gestational hypertension. Fifty four (90%) mothers needed lower uterine caesarian section. Forty four (73.33%) delivered preterm before 36 weeks of pregnancy. Low birth weight (<2.5kg) babies were 30(50%), very low birth weight (<1.5kg) were 16(26.66%). Intrauterine growth retardation (IUGR) were 18(30%) and Appropriate for gestational age( AGA) were 14(23.33%). Respiratory distress 30(50%) were the most common cause of admission, other associated problems were perinatal asphyxia (PNA) with seizure and meconium aspiration syndrome and to rule out sepsis in suspected cases. Nine (15%) needed ventilator care and 6(10%) needed nasal continuous positive airway pressure (NCPAP) for respiratory problem. 6(10%) babies were expired and 54(90%) survived. Average hospital stay were 18.32(±10.68) days with a highest hospital stay of 49 days and the lowest 4 days.Conclusion : Maternal hypertensive disorder of pregnancy is associated with neonatal morbidity.Northern International Medical College Journal Vol.6(2) 2015: 57-60
Nutritional status and knowledge about nutrition during pregnancy among pregnant and postpartum women
Authors: Salim Farhana , Begum Nasreen
Published: May 2015

Objective : To assess the nutritional status and the level of knowledge about nutrition during pregnancy among pregnant and postpartum women attended community clinics in selected villages.Methods : This descriptive, cross-sectional study was done in three selected villages of Sirajganj, Kishoreganj and Tangail districts during July 2014. Fifty six pregnant and 46 postpartum women were selected from community clinics by purposive sampling technique. Data were collected through face to face interview by a pretested questionnaire. Height and weight were measured to calculate BMI health workers of community clinic.Results : The results of the study revealed significant number (23.5%) of pregnant women were found to be underweight by calculating the BMI. However, knowledge about the consequences of malnutrition in pregnancy, and the amount and types of food to be taken during pregnancy was found unsatisfactory. The level of education and occupation were not significantly associated with nutritional status of the respondents.Conclusion : The study revealed that high percentage of rural mothers was malnourished and the knowledge about nutrition during pregnancy was found unsatisfactory. Therefore, implementation of nutritional programs with specific emphasis on nutritional education in pregnancy during the antenatal visits is considered essential for rural women.Northern International Medical College Journal Vol.6(2) 2015: 61-63
Activity of disinfectants related to food hygiene and sanitation
Authors: Lima Farzana Rahman , Ahmed Shahabuddin
Published: May 2015

Objectives : To observe the activity of disinfectants related to food hygiene and sanitation and to determine the germicidal effect of those disinfectants against various microorganisms adhered to different surface materials in relation with time and concentration.Materials and Methods : The study was carried out in the Institute of Nutrition and Food Science (INFS) of Dhaka University, Dhaka during FebruarySeptember 2002. The disinfectants were sodium hypochlorite (NaOC1) and calcium hypochlorite Ca(OCl)2. Minimum Inhibitory Concentration (MIC), Qualitative and Quantitative suspension test, Phenolic co-efficient test and Germicidal effect of NaOC1 and Ca (OCI)2 against E coli and Staph aureus on different surface materials were tested. Surface materials of the experiment were 4 sq cm of wood, tin, rexene, formica and ceramic tile pieces.Results : The disinfectants related to food hygiene and sanitation was studied critically. The concentration of 2% and 8% for Ca(OC1)2 and NaOCl respectively would be ideal. Gram negative bacteria (E coli) was more sensitive to NaOCl than gram positive bacteria (Staph aureus) and gram positive bacteria was more sensitive to Ca(OC1)2 than gram negative bacteria on all the five surface materials.. The Germicidal effect of Ca(OC1)2 was found better than that of NaOC1.Conclusion : Considering the result it can be concluded that both the hypochlorite are more active and effective disinfectant against E coli and Staph aureus. Therefore, to prepare the wholesome and safe food Ca(OC1)2 and NaOC1 are considered as ideal disinfectant for rendering food preparing places and sites free from contamination.Northern International Medical College Journal Vol.6(2) 2015: 64-67
Study on neonates who received exchange transfusion at Dhaka shishu hospital
Authors: Rahman Maksudur , Sarkar Probir Kumar , Nazrin Tahera , Chowdhury Khanta , Jahan Rawshan Akter , Islam M Shohidul , Akhter Fahmuda
Published: May 2015

Objective : To identify etiology of neonatal hyperbilirubinaemia requiring Exchange Transfusion (ET) and to see the complications of ET and its outcomes.Methods : This prospective study was done in a tertiary hospital. Total 39 admitted newborn babies with hyperbilirubinaemia who required exchange transfusion were enrolled and all information regarding etiology of jaundice, laboratory investigations, complications and outcomes of cases were documented and analyzed.Results : During one year of study period ET was done in 39 neonates. Among them 16 (41%) cases were male and 23(59%) were female. Fifteen (38%) babies were preterm and 24(62%) babies were term. Fifteen (38%) babies were preterm low birth weight (PLBW) with or without septicaemia as comorbidity. Twelve (31%) cases had only hyperbilirubinaemia. Rh-incompitability was seen in 17 (44%), ABO incompitability in 15(38%) cases and unknown cause in 7(18%) neonates. Common complications seen were hypoglycaemia in 7(18%) and thrombocytopenia in 6(15%) neonates. Two (5%) neonates who died had comorbidity.Conclusion : Exchange transfusion is required mostly in Rh incompitability and common complications of ET were hypoglycaemia and thrombocytopenia.Northern International Medical College Journal Vol.6(2) 2015: 70-72
Influence of Climate Change and Meteorological Factors on Houston’s Air Pollution: Ozone a Case Study
Authors: Liu Lei , Talbot Robert , Lan Xin
Published: May 2015

We examined the past 23 years of ground-level O3 data and selected meteorological parameters in Houston, Texas, which historically has been one of the most polluted cities in the United States. Both 1-h and 8-h O3 exceedances have been reduced significantly down to single digit yearly occurrences. We also found that the frequency of southerly flow has increased by a factor of ~2.5 over the period 1990–2013, likely suppressing O3 photochemistry and leading to a “cleaner” Houston environment. The sea breeze was enhanced greatly from 1990 to 2013 due to increasing land surface temperatures, increased pressure gradients, and slightly stronger on-shore winds. These patterns driven by climate change produce a strengthening of the sea breeze, which should be a general result at locations worldwide.
Determination of Citrus Limonoid Glucosides by High Performance Liquid Chromatography Coupled to Post-Column Reaction with Ehrlich’s Reagent
Authors: Breksa Andrew , King Darwin , Vilches Ana
Published: May 2015

A method for the identification and quantification of citrus limonoid glucosides in juices, based upon high performance liquid chromatography (HPLC) separation coupled to post-column reaction with Ehrlich’s reagent, has been developed. This method utilizes a phenyl stationary phase and an isocratic mobile phase. Limit of detection for the method was determined to be 50 ng of limonin glucoside. Limonin glucoside and the other limonoid glucosides tested responded equivalently to the post-column reaction with Ehrlich’s reagent suggesting that limonin glucoside may be used as a surrogate for the quantification of other limonoid glucosides, including nomilin, deacetyl nomilin, nomilinic acid, deacetyl nomilinic acid, and obacunone glucosides. For most juice samples, no sample treatment is required to determine limonin glucoside content. Concentration by solid phase extraction is recommended for juices with low levels of limonin glucoside and to facilitate the detection and quantification of other limonoid glucosides present at low concentrations. With the exception of blood oranges, the method was successfully applied to the analysis of juices from a variety of citrus varieties.
Fast Chromatographic Method for Explosive Profiling
Authors: Stefanuto Pierre-Hugues , Perrault Katelynn , Focant Jean-François , Forbes Shari
Published: May 2015

Security control is becoming a major global issue in strategic locations, such as airports, official buildings, and transit stations. The agencies responsible for public security need powerful and sensitive tools to detect warfare agents and explosives. Volatile signature detection is one of the fastest and easiest ways to achieve this task. However, explosive chemicals have low volatility making their detection challenging. In this research, we developed and evaluated fast chromatographic methods to improve the characterization of volatile signatures from explosives samples. The headspace of explosives was sampled with solid phase micro-extraction fiber (SPME). Following this step, classical gas chromatography (GC) and comprehensive two-dimensional GC (GC×GC) were used for analysis. A fast GC approach allows the elution temperature of each analyte to be decreased, resulting in decreased thermal degradation of sensitive compounds (e.g., nitro explosives). Using fast GC×GC, the limit of detection is further decreased based on the cryo-focusing effect of the modulator. Sampling of explosives and chromatographic separation were optimized, and the methods then applied to commercial explosives samples. Implementation of fast GC methods will be valuable in the future for defense and security forensics applications.
The Multiscale Entropy Algorithm and Its Variants: A Review
Authors: Humeau-Heurtier Anne
Published: May 2015

Multiscale entropy (MSE) analysis was introduced in the 2002 to evaluate the complexity of a time series by quantifying its entropy over a range of temporal scales. The algorithm has been successfully applied in different research fields. Since its introduction, a number of modifications and refinements have been proposed, some aimed at increasing the accuracy of the entropy estimates, others at exploring alternative coarse-graining procedures. In this review, we first describe the original MSE algorithm. Then, we review algorithms that have been introduced to improve the estimation of MSE. We also report a recent generalization of the method to higher moments.