bluuebunny/crossref_metadata_2025 huggingface dataset:
Waist Circumference was Positively Correlated with Chemerin, Retinol-Binding Protein 4 and hsCRP
Authors: Herminawati Lucia , Meiliana Anna , Wijaya Andi
Published: October 2015

BACKGROUND: Central obesity is associated with various chronic metabolic disorders characterized by abnormal cytokine production, increased acute phase reactants, and activation of inflammatory signaling pathways. This study was aimed to investigate the association of waist circumference, chemerin, and retinol binding protein (RBP)-4 with inflammation in men with central obesity.METHODS: The research was conducted with a crosssectional design involving 68 centrally obese male subjects aged 30 to 60 years old, with waist circumference (WC) >90 cm. All subjects fulfilled the inclusion and exclusion criteria. Anthropometric parameters, fasting glucose, creatinine, SGOT, SGPT and hsCRP were measured. Serum concentrations of chemerin and RBP4 were measured by ELISA.RESULTS: The trend lines showed that chemerin, RBP4, and hsCRP increased with WC. Pearson correlation test showed a positively significant correlation between WC and hsCRP (r=0.242, p<0.05); and also between chemerin and hsCRP (r=0.244, p<0.05) and RBP4 (r=0.321, p<0.01). Subjects were stratified into four groups based on their chemerin and RBP4 levels (high chemerin/high RBP4, high chemerin/low RBP4, low chemerin/high RBP4, or low chemerin/low RBP4). Subjects who were in the high chemerin/low RBP4 group were more likely to have high level of inflammation (47.6%), but subjects with high chemerin/high RBP4 showed low level of inflammation (42.9%) as compared with the other three groups.CONCLUSIONS: We concluded that increased WC was correlated with elevated levels of chemerin, RBP4, and hsCRP. High chemerin was correlated with increased level of RBP4 as well as with high level of inflammation.KEYWORDS: waist circumference, chemerin, RBP4, hsCRP, inflammation
The Correlation between Lipoprotein-Associated Phospholipase A2 and Atherosclerosis (ox-LDL) in Centrally Obese Men
Authors: Ari Priscilla Dian , Susanti Ellis , Patellongi Ilhamjaya
Published: October 2015

BACKGROUND: Obesity is closely associated with atherosclerosis. Obesity and atherosclerosis are closely associated with inflammatory disease. Atherosclerosis constitutes a multifactorial disorder affecting the arterial wall, which is initiated by dyslipidemia and excerbated by inflammation. Plasma levels of lipoprotein-associated phospholipase A2 (Lp-PLA2) and oxidized low density lipoprotein (ox-LDL) have been identified as risk factors for cardiovascular disease.  Lp-PLA2 is the sole enzyme responsible for the hydrolysis of oxidized phospholipids (oxPL) on LDL particles in atherosclerosis plaque. Plasma level of oxLDL is associated with inflammation and plays an important role in the development of atherosclerosis. The aim of this study was to assess the correlation between Lp-PLA2 and atherosclerosis (oxLDL) in centrally obese men.METHODS: This was a cross-sectional study involving 71 men with central obesity with waist circumference >90 cm, aged 30-60 years old. Lp-PLA2 measurement was done by sandwich enzyme immunoassay. oxLDL measurement was done by ELISA method. RESULTS: Results of this study showed that central obesity correlated positively with oxLDL (r=0.258; p=0.040) and Lp-PLA2 >422 ng/mL correlated positively with oxLDL (r=0.331; p=0.042).CONCLUSIONS: We conclude that there is a correlation of Lp-PLA2 with atherosclerosis (oxLDL) in men with central obesity.KEYWORDS: obesity, Lp-PLA2, oxLDL, atherosclerosis
La cláusula ‘ex fide bona’ y su influencia en el ‘quantum respondeatur’ como herramienta para recuperar el equilibrio patrimonial en derecho romano
Authors: San Martín Neira Lilian C.
Published: October 2015

Este artículo se refiere a la relación existente entre la cláusula ex fide bona y la cuantía de la condena en derecho romano. Mediante la exégesis de dos pasajes del Digesto se pone en evidencia que, gracias a la elasticidad de la cláusula ex fide bona, los juristas romanos utilizaron el quantum respondeatur como un mecanismo para restablecer el equilibrio patrimonial, excluyendo de la summa condemnationis cantidades que en principio habrían debido incluirse. En consecuencia, en Roma la buena fe no era solo un mecanismo de integración del contrato mediante la ampliación de las obligaciones contraídas por las partes, sino también un mecanismo de atenuación de dichas obligaciones, cuando su exigencia en términos literales resultaba contraria al equilibrio propio de los contratos de buena fe.
Effectiveness of primate seed dispersers for an “oversized” fruit, Garcinia benthamii
Authors: McConkey Kim R. , Brockelman Warren Y. , Saralamba Chanpen , Nathalang Anuttara
Published: October 2015

The largest fruits found in tropical forests may depend on complementary seed dispersal strategies. These fruits are dispersed most effectively by megafauna, but populations can persist where megafauna are absent or erratic visitors. Smaller animals often consume these large fruits, but their capacity to disperse these seeds effectively has rarely been assessed. We evaluated the contributions of gibbons (Hylobates lar) and other frugivores in the seed dispersal of the megafaunal fruit Garcinia benthamii, using the SDE (seed dispersal effectiveness) landscape. Gibbons preferentially consumed G. benthamii fruits and were the main seed disperser that we observed. However, gibbons became satiated when availability was high, with 57% of fruits falling to the ground unhandled. Recruitment of seedlings from gibbon‐dispersed seeds was also very low. Elephants consumed G. benthamii fruit, but occurred at low density and were rare visitors to the trees. We suggest that gibbons might complement the seed dispersal role of elephants for G. benthamii, allowing limited recruitment in areas (such as the study site) where elephants occur at low density. Fruit availability varied between years; when availability was low, gibbons reliably consumed most of the crop and dispersed some seeds that established seedlings, albeit at low numbers (2.5 seedlings per crop). When fruit availability was high, the fruit supply overwhelmed the gibbons and other arboreal frugivores, ensuring a large abundance of fruit available to terrestrial seed dispersers. Although gibbons effectively dispersed more seeds at these times (20.7 seedlings per crop), there was the potential for elephants to move many more seeds. Complementary seed dispersal strategies may be important for megafaunal fruit, because they ensure that very large fruits are able to benefit from megafaunal dispersal but also persist where this dispersal becomes erratic. However, our data suggest that smaller seed dispersers might not be capable of replacing large dispersers, leading to potential changes in landscape‐scale dispersal patterns where megafauna are absent.
A Simulation Model for Accurate Prediction of Uneven Proppant Distribution in the Marcellus Shale Coupled with Reservoir Geomechanics
Authors: Yang Sheng , Chen Zhangxin , Wei Yizheng , Wu Keliu , Shao Lei , Wu Wei
Published: October 2015

Proppant distribution directly affects the effectiveness of hydraulic fracturing treatment, and significantly impact well production. In most situations, proppants are not uniformly distributed in hydraulic fractures and most proppants cannot be effectively transported into the far ends of fractures from wellbore. As a result of uneven proppant distribution and the ductile and soft geomechanical properties of the Marcellus shale, the reduction in hydraulic fracture conductivity varies greatly from cluster to cluster in a shale reservoir during reservoir pressure depletion. However, the influences of accurate prediction of uneven proppant distribution in hydraulic fractures and geomechanics on well productivity have been ignored in previous simulation studies.

In this study, a reservoir simulation model for accurate prediction of uneven proppant distribution is developed. This dual-permeability model is coupled with reservoir geomechanics to illustrate the interaction of stress changing and multiphase flow within hydraulic fractures. History matching from a production well in the Marcellus shale is performed to validate our model. In addition, simulations using different matrix permeability are performed to demonstrate the impact of matrix permeability, along with the effect of proppant distributions and geomechanical properties on well performance.

The simulation results show that gas production varies significantly due to different proppant distribution and geomechanical properties. Coupled geomechanical simulation results clearly indicate that the proppant embedding effects are also noticeable due to soft rock mechanical properties and uneven proppant distribution. This paper provides operators with a clear insight of influences of uneven proppant distribution and geomechanics on shale gas performance, optimization of a well treatment design, and an extensive view about the long-term production behavior for the Marcellus shale.
Management of Internal Corrosion Threats Can Improve Long Term Integrity of Midstream Pipelines
Authors: Hanger N. , Tossey B. , Eckert R.
Published: October 2015

Midstream pipelines moving produced fluids from shale plays are susceptible to a number of potential internal corrosion threats. Although the quality of transported commodities is governed by sales agreements between producers and pipeline operators, there are practical limitations to continually monitoring and enforcing fluid compositional parameters at exchange points. Since many midstream pipeline systems were constructed in the last five years, the integrity threat of internal corrosion has yet to have an impact on operation and maintenance costs; however, corrosion is an issue that may emerge over time. Experience from over 50 years of gathering, storage and transmission pipeline corrosion history can be applied to proactively managing internal corrosion of midstream pipelines, helping to ensure the life of the assets for decades to come.

Owners and operators of new midstream pipelines have an advantage over owners of older systems when developing a corrosion management plan. First, the fact that the pipeline system is new and has been subjected to no or few asset transfers (e.g. sold to another party), has not been rerouted, repaired, or otherwise modified from the as-installed condition, and likely has up-to-date construction and inspection records, can provide a solid foundation for baseline condition assessments. Second, these up-to-date design documents, construction records, and operating data can be used in conjunction with flow models and corrosion rate estimates to identify locations along the pipeline that may be susceptible to internal corrosion threats before pipeline wall loss occurs. These locations can then be monitored to provide early indications of internal pipe wall loss and to determine the need for corrosion mitigation.

A corrosion allowance in pipeline design is typically based on an estimated general corrosion rate at the assumed operating conditions, however; this allowance may not be sufficient to address localized corrosion mechanisms that often occur at a higher rate. In addition, actual operating conditions may change over time, as will the rate and type of internal corrosion mechanisms. The expectation that the pipeline system will not corrode beyond the design basis during the life of the asset can lead to catastrophic, unnecessary consequences and expose the operator to significant business risk if assurance measures are not in place. To reduce this risk, pipeline owners/operators can develop and implement proactive corrosion management plans that are scientifically sound, guided by industry standards and best practices, compliant with regulations, and maintained by corrosion professionals.
Refracturing Early Marcellus Producers Accesses Additional Gas
Authors: Rodvelt Gary , Ahmad Mian , Blake Austin
Published: October 2015

Early completions in the Marcellus formation consisted of long stage sections (up to 450 ft between injection points) with few entry points in an effort to complete the wells in a timely fashion. Volumes of fluid and proppant were a function of the number of stages based on the geometric division of the wellbore. Concerns regarding stress shadowing and proppant placement outweighed formation considerations at that time. In many cases, economics were a driving factor with respect to the number of stages an operator was willing to perform. With increased equipment availability, job costs decreased and operators performed more stages per well with shorter spacing between clusters. Initial production figures confirmed the need to shorten cluster spacing and stage lengths; but, questions remained regarding the previous wells treated with longer stages and larger spacing between clusters and whether these wells still had commercial quantities of gas to be accessed.

Since November of 2013, seven wells were restimulated using a new diversion process that allowed the operator to reduce the cluster spacing. In one case, the original failure to reach total depth (TD) with casing provided an opportunity to stimulate new areas of the rock in an openhole environment. This paper details the process applied to the seven wells and confirms access to significant additional reserves based on production results. Use of an analytical production simulator confirms improvement to the productivity index (PI) and EUR30 forecast. One operator has confirmed more than 200 candidates for this refracturing process.
Comparing Strategies for Optimizing Horizontal Shale Completions by Projecting Pilot Well Measurements Across Laterals
Authors: Lili Xu , Yates Malcolm , Anifowoshe Olatunbosun , Uschner-Arroyo Natalie , Yang Yu , MacPhail Keith
Published: October 2015

Unconventional shale-gas reservoirs are usually highly laminated with vertical and lateral heterogeneity. The elastic mechanical properties are highly anisotropic along the different orientations parallel and perpendicular to the bedding. The formation heterogeneity, elastic anisotropy, and structural complexity affect the stress field both near and far from the wellbore and thus the fracture containment, fracture initiation pressure, and breakdown pressure. A better understanding of the formation properties and in-situ stress can be achieved by an advanced logging program. Many studies have shown improved production in the lateral wells by implementing an engineered completion design using advanced sonic logs and other high-tier logs. The importance of understanding these properties in the lateral wells also raised questions including whether we can predict lateral log responses from pilot wells and whether the formation is laterally homogenous.

In this study, we compared the projected lateral logs from pilot wells with the actual lateral logs to shed insights on the important question of formation heterogeneity. Different techniques were applied including a gamma ray method and an advanced 3D near-well structural model. The 3D model took advantage of the valuable information from borehole geology interpretation of image logs such as bedding, fractures, and faults to build high-resolution near-well structures. It was then used as a framework to model the reservoir properties and far-field stress using methods including a layer-cake and a finite-element approach. The output of the model showed the lateral heterogeneity of the reservoir by comparing the lateral section with the pilot well.

The reservoir properties from these techniques described above were then incorporated and evaluated as part of the completion design workflow, which focused on both near-wellbore and far-field modeling. The results showed the benefits and limitations of each propagating modeling technique for optimizing the completion design and shed light on the realization of being able to project the pilot logs across a single horizontal well or an entire pad.
Evaluation Of The Effect Of Stress-dependent Permeability On Production Performance in Shale Gas Reservoirs
Authors: Ali Tariq A. , Sheng James J.
Published: October 2015

It is very important to predict well performance of unconventional reservoirs before designing a field development plan. Although these reservoirs have high initial production rates, it is common that their production performance decline faster than conventional reservoirs. Therefore, it is necessary to identify the reasons behind the reduction of production performance. One of these reasons is the increase in stress as a result of continuing production and decrease in pore pressure.

The main objective of the research presented in this paper is to model the effects of stress-dependent permeability for both hydraulic and natural fractures on the production performance of shale gas reservoirs. We generate a new stress-dependent compaction table to history match the performances of a single well in Haynesville formation. We also investigate the optimum operation conditions at which no sever reduction in production performance occurs.

The results of more than 50 simulation cases indicate that stress-dependent properties (permeability and porosity) have a significant effect on reservoir performance. The study also indicate that hydraulic fractures lose over 90% of its permeability with most of the permeability loss occurring at late time of production. The study also shows that we can delay the effect of stress-dependent properties by either increasing initial hydraulic fracture conductivity or operating wells at low drawdown pressure.
Dynamic Assessment of Induced Stresses and In-situ Stress Reorientation during Multi-Stage Hydraulic Fracturing in Unconventional Reservoirs
Authors: Reddy Liliia , Jenkins Andrew , Fathi Ebrahim
Published: October 2015

This paper has been dedicated to the optimization of multi-stage hydraulic fracturing by providing a more thorough understanding of fracture and reservoir stress behavior. This is accomplished by the use of a fully coupled fracture propagation simulator that couples fracture mechanics and fluid dynamics, unlike past studies, which observe only simple interactions. The underlying objective is to eliminate the misappropriated energy caused by inter-fracture stress interaction and stress reorientation surrounding the induced fracture network by assessing stress magnitude as a function of operation conditions.

This study is based upon an in-house numerical simulation model developed for hydraulic fracture propagation based upon the linear elastic fracture mechanic "LEFM" using finite element method. The elastic response of the 2-D solid medium and the fluid flow within the fracture is coupled to provide a more realistic depiction of these interactions. The magnitude of stress variation and reorientation is calculated in surrounding areas of simultaneous and sequential hydraulic fracturing of a horizontal well for a wide range of hydraulic fracturing propagation regimes for both homogenous and compositional models.

Our study clearly shows that there is an optimum distance between hydraulic fractures below which, the change (variation) in magnitude and orientation of stresses leads to significant change in fracture geometry and propagation rate. This has been impacted mainly through mechanical interaction that leads to higher compressive stress concentrations between fractures. The mechanical interaction becomes stronger by increasing the number of fractures or altering the fracture spacing. The effects have also been investigated in a composite reservoir model with different mechanical properties (i.e., Young's modulus and Poisson's ratio), and operational conditions, such as injection rate and volume. Mechanical properties of different layers in a composite reservoir model significantly impact the fracture geometry and propagation rate when the fracture intercepts different layer boundaries. The magnitude of change in stresses and stress reorientation is also quantified in cross sections with respect to the fracture plane as the fracture propagates.

This study provides an advanced understanding of multiple hydraulic fracturing stimulation and dynamics of fracture geometry, propagation rate and stress change in surrounding using our unique fully coupled hydraulic fracturing simulator. Moreover, it provides quantitative analysis of induced stresses and in-situ stress reorientation. The work is important for the optimization of Multi-stage hydraulic fracturing in unconventional reservoirs.
Real Time Tracking of Fracture Propagation During Air Injection as an Alternative Fracturing Fluid
Authors: Hascakir B.
Published: October 2015

Hydraulic fracturing is a proven technology that is implemented through injecting highly pressurized water into tight formations. The excessive amount of water use during the process poses serious environmental problems. To address this issue, we propose and study the feasibility of a new fracturing technology utilizing air injection as an alternative fracturing fluid for tight oil and gas reservoirs. Samples from Eagle Ford and Green River formations are selected to study due to their compositional differences; carbonate rich and kerogen rich, respectively. Samples were first characterized with X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Thermogravimetric Analysis (TGA) to determine their mineralogical and organic content. A special core holder was designed to visualize the fracture formation during experiments with X-Ray Computed Tomography (CT). CT scan results were analyzed for fracture formation and propagation during air injection. Experimental results show that the clay content and type during air injection play an important role on fracture formation. It has been found that the alterations in clays at elevated temperatures contribute to keep the formed fracture apertures open due to the cementing behavior of clays at high temperatures. Kerogen was found to also contribute to the formation of microfractures due to its thermal decomposition and the thermal expansion of formed gases at elevated temperatures. Furthermore, the decomposition of inorganic content, especially the carbonate content of shale samples, enhances the fracture formation. Hence, all clay rich, carbonate rich, and kerogen rich shale samples show a trend that favors effective fracturing with air. CT scan results also validate the formation and propagation of these effective fractures, and CT scans taken after one day of the core flooding experiments prove that the fractures remain open even without proppant addition. Because air is an abundant, cheap, and easy to handle injection fluid, it is an attractive alternative to water for fracturing. Our experimental results support the use of air as an alternative fracturing fluid in a promising, feasible, and low cost method for fracturing tight oil and gas reservoirs.
Refracturing Design for Underperforming Unconventional Horizontal Reservoirs
Authors: Krenger J. T. , Fraser J. , Gibson A. J. , Whitsett A. , Melcher J. , Persac S.
Published: October 2015

This paper discusses design considerations to increase the estimated ultimate recovery (EUR) on underperforming wells in a refracturing scenario. A method for, and case histories of, using an environmentally acceptable, self-removing particulate diverter that has proven to be successful in the refracturing efforts of horizontal unconventional reservoirs are provided. This method is typically chosen for its low cost, self-assembly, and self-removal. An outline of the design process for refracturing and post-refracturing procedures is included. The ability to add reservoir contact, restore conductivity, remediate blockage, and address depleted reservoir pressure make this technique desirable.

Different strategies can be applied when using this technique and are typically customized to the particular candidate well selected for the refracturing treatment. The treatment designs for the wells discussed in this paper were designed to increase EUR. Candidate wells for refracturing typically fall into one or more categories: understimulation occurred in the original completion, production damaging mechanisms are present, a low investment lease retention strategy was originally required, or a pressure-sink mitigation strategy is necessary for infill completions. Candidates in this paper fall into the understimulated category. A typical procedure consists of casing inspection, wellbore cleanout, possible addition of perforations, and flowback considerations.

In this study, different Haynesville shale refracturing treatments, results, and diagnostics are compared. The evolution of treatment design components, such as carrier fluid, fluid volume, proppant volume, and diverting methodology, is explained. The results and underlying theory of these changes are outlined. Pre/post-treatment production is compared, along with treatment pressure trend analysis and microseismic data.

Although performing secondary stimulation treatments is becoming more common, the industry's focus on improving production decline curves has led to a surging interest in refracturing horizontal unconventional reservoirs. Decline rates in unconventional reservoirs tend to be more rapid compared to conventional reservoirs because of their ultralow permeability, limited reservoir contact, and original completion strategy. Refracturing of these reservoirs enables the recovery of hydrocarbons trapped by these restrictions.
Using the Wrong Method to Estimate Stress From Depletion Causes Significant Errors in Predicting Wellbore Integrity and Fracture Geometry
Authors: Narasimhan Santhosh , McCleary Matt , Fluckiger Samuel D , Gray James , Cherian Bilu V. , Shaikh Hamza , Olaoye Olubiyi
Published: October 2015

When calculating the downhole stresses affecting a wellbore during depletion it has become a standard industry practice to assume only the pore pressure changes, and not the rock mechanical properties. This assumption has the potential to underestimate the total horizontal stress (Sh) causing unrealistic fracture containment. It will also overestimate the effective horizontal stress (Sh' = Sh - Biot * Pore Pressure) for open-hole wellbore failure. High effective horizontal stress assumption can potentially transform rock from brittle to ductile behavior and failure mechanics from shear to compaction and the model becomes overly conservative. Ductile and compaction failure can cause changes in well integrity, as well as changes in fracture geometry from offset infill wells. This paper will document changes in rock properties in the Bakken formation during variable depletion (10% to 65%) and recalculate rock properties (velocities, mechanical properties - Young's modulus, Poisson's ratio, and Biot's anisotropic compressibility constant) as a function of effective stress due to production in order to accurately calculate fracture geometry at an offset well and parent well bore integrity. Hydraulic fracturing simulations are performed to simulate well communication between the fractured well and the depleted parent well along with the potential to re-fracture the parent well using the pore pressure, linear, and non-linear models. Laboratory testing performed on rock samples is shown to validate the non-linear model.
Simulation of Cement Slurry Flow to Assess the Potential for Voids and Channels in Wellbore Cementing Processes
Authors: Grasinger Matthew , Li Zichang , Vuotto Alex , Brigham John , Iannacchione Anthony , Vandenbossche Julie
Published: October 2015

A numerical approach is presented to simulate the non-Newtonian flow of a wellbore cementing process to quantify the potential for poor drilling mud displacement efficiency and bond strength development between the cement annulus and rock formation. The approach consists of using the lattice Boltzmann method with a Bingham plastic constitutive model to represent the cement flow behavior. The lattice Boltzmann method is a pseudo-particle, mesoscale approach that naturally models complex flows in a computationally efficient manner, but has thus far seen limited use for capturing such slurry (or similar) flows. Results from the model are presented for a wellbore cementing process with various annular configurations and cement slurry properties. In particular, the results consider irregularities and imperfections in the shape of the rock formation surface, as well as changes in the cement flow properties (e.g., viscosity), as could be affected by variations in mix and/or the pumping process. These results show an array of circumstances in which poor drilling mud displacement efficiency and bond strength development between the cement column and rock formation does or does not occur as the cement is pumped into the wellbore annulus. Lastly, potential future work and developments are discussed for the numerical approach to address other failure mechanisms of zonal isolation, which are still poorly understood mechanistically.
Real Time Prediction and Classification of Torque and Drag During Drilling Using Statistical Learning Methods
Authors: Hegde Chiranth , Wallace Scott , Gray Ken
Published: October 2015

A method for predicting torque and drag has been developed which is based on statistical learning models and which utilizes parameters routinely measured while drilling. Real time prediction of torque and drag during drilling has particular significance in on-the-fly rig floor operational modifications and in overall drilling optimization. These statistical methods are readily incorporated into real time drilling optimization procedures, first through a passive diagnostic tool, and subsequently through an integrated real-time control loop.

This paper presents statistical learning techniques such as bootstrapped regression, random forests, and support vector machines for prediction of downhole torque. An analysis of the aforementioned methods is carried out to evaluate computational efficiency of the processes. The statistical package R has been employed for processing and visualization of data and for displaying results. A comparison is made to real time ROP prediction carried out in previous work, to assess the relationship between predicted torque and ROP. A method is proposed to use classification techniques for predicting whether drilling is proceeding at the optimal level.

Torque values were accurately predicted with all three methods discussed in this paper. However, scalability of the methods must be considered, owing to the increased computational efficiency that is required. Computationally efficient and robust systems are of high priority for field applicability. To that end, ensemble techniques were analyzed along with the aforementioned methods and runtimes were evaluated for all of the methods employed. Results show that this method can be incorporated into real time drilling situations, with attending low runtimes. Development of more accurate methods will require additional computational power and the use of ensemble techniques. Classification proves to be a good technique whenever optimization is required, as indicated by real time predictions. Classification techniques illustrated in this paper explore the viability of various options for correcting undesirable drilling performance.

This paper presents state of the art statistical learning techniques for predicting torque and drag during drilling. Previous torque and drag calculations using finite element models provide a good cross reference with this statistical model for indicating operational anomalies. Unexpected values of torque may forecast imminent drilling problems. These methods can be utilized for prediction of drilling problems and proactive methods for avoiding them, and applied in optimized drilling procedures.
Consumer’s Risk Perception of Genetically Modified Food and its Influencing Factors: Based on the Survey in Jiangsu Province, China
Authors: Liu Ruixin , Wu Linhai , Shan Lijie , Li Hua
Published: October 2015

Safety has always been the focus of debate on genetically modified food (GMF). To understand consumers’
risk perception of GMF and its influencing factors, this study investigated 300 consumers from 6 cities in Jiangsu province,
China by questionnare. The data were analyzed by using independent sample t-test, one-way ANOVA and principal
component analysis. The results showed that most consumers worried about the safety of GMF and hoped GMF to be labeled
with identity; meanwhile, their purchase intention of GMF was not high. Some of consumer characteristics including
gender, education background, personal annual income, and with at least one child under 18, significantly influenced
their risk perception of GMF. Furthermore, the main factors significantly influencing the consumers’ risk perception of
GMF were as follows in order of influence degree: health risks (0.386), ecological risk (0.187), and social risk (0.163).
Consequently, the government should strengthen the popularization of scientific knowledge on genetically modified technology
as well as GMF and simutaneously reinforce standardized management of GMF label.
Novel Pd Nanocubes Supported on Activated Carbon as a Catalyst for the Suzuki-Miyaura Coupling Reaction
Authors: Shi Zhenpeng , Bai Xue-Feng
Published: October 2015

Palladium nanocubes with diameters of 6~10 nm have been successfully synthesized by a simple reduction
route with the assistance of PVP as stabilizing agent and KBr as a capping agent. The palladium nanocubes supported on
activated carbon (Pd/C) were prepared by a physical absorption method. The-prepared Pd/C catalysts were characterized
by X-ray diffraction (XRD), transmission electron microscopy technology (TEM), thermogravimetric analyzer (TGA) and
X-ray photoelectron spectroscopy (XPS). The results demonstrated that the palladium nano particles with the facecentered-
cubic structure were uniformly supported on the activated carbon. It was shown from experimental results that
the product yield for the Suzuki-Miyaura reaction between aryl bromides with aryl boronic acid attains more than 90%
and has no significant loss of catalytic activity after five reaction cycles.
Deep Analysis of Data Mining Method in Personalized Information System of University Library
Authors: Wang Kunpeng
Published: October 2015

In order to discuss the application method and execution process of data mining in personalized information
system establishment of university library, the thesis introduces existing condition of university library and insufficiency
of the information service system. At the same time, data mining technology is introduced to simply describe the data
mining process and introduce two top applications of the data mining technology in personalized library information system,
namely student interest guidance quality and establishment of relevancy rule. Furthermore, more classical algorithms
(FP-growth algorithm and K-mean clustering algorithm) are introduced in the data mining technology in detail. The data
mining technology is a new data processing method. Nowadays, as for high flux reactor data analysis, data mining technology
becomes more and more important in the construction process of personalized library information system.
Influence of Coupler and Buffer on Dynamics Performance of Heavy Haul
Locomotive
Authors: Tianwei Qu , Weihua Ma , Dong Wu , Shihui Luo
Published: October 2015

Aimed at the safety problem of the locomotive under the dynamic braking condition, this paper analyzes the
influence of the coupler and buffer system. The coupler reposition methods of the large rotation angle coupler and the
small rotation angle coupler under longitudinal coupler press force were compared. The influence of coupler and buffer
system to the dynamics performance of locomotive was researched through dynamic simulation. Results show that the
longitudinal coupler press force afforded by large rotation angle coupler with coupler shoulder, is larger than that of small
rotation angle coupler.
The Effect of Foam Rolling Duration on Hamstring Range of Motion
Authors: Couture Grace , Karlik Dustin , Glass Stephen C , Hatzel Brian M
Published: October 2015

Musculoskeletal health benefits from flexibility training and maintaining a functional, or sport specific, range of motion is important to one’s overall fitness. Commercial foam rollers are commonly used in gyms, therapy clinics and homes, yet data are lacking on the optimal rolling duration and effect on range of motion.

Purpose :

The purpose of this study was to examine the effect of varied durations of a commercial foam roller treatment on hamstring range of motion.

Methods :

The knee extension range of motion of 33 college aged men and women (age= 20±1.5y, mass= 72.2±10.8 kg) was assessed after a short (2 sets of 10s) and long (4 sets of 30s) duration of hamstring self-administered myofascial release using a commercial foam roller. A one way ANOVA was performed to compare the mean knee extension angle for each condition to baseline measures.

Results :

Results indicated that neither the short duration (67.30 ± 10.60 deg) nor long duration (67.41 ± 10.81 deg) rolling condition produced significant increases in knee extension compared to baseline (67.70 ± 9.90 deg).

Conclusion :

Self-administered foam rolling for a total duration of up to 2 minutes is not adequate to induce improvements in knee joint flexibility. Contributing factors may include the amount of pressure imparted by the commercial roller as well as duration of treatment.
Current Evidence for the Use of Laminar Flow in Reducing Infection Rates in Total Joint Arthroplasty
Authors: James M , Khan W.S , Nannaparaju M.R , Bhamra J.S , Morgan-Jones R
Published: October 2015

Since the introduction of laminar air flow in orthopaedic theatres by Sir John Charnley, it has widely become accepted as the standard during orthopaedic procedures such as joint arthroplasty. We present a review of available current literature for the use of laminar flow operating theatre ventilation during total joint arthroplasty and examines the effectiveness of laminar flow ventilated operating theatres in preventing post-operative wound infection. Results of our findings suggest that while bacterial and air particulate is reduced by laminar air flow systems, there is no conclusive effect on the reduction of post-operative wound infections following total joint arthroplasty. We conclude that a combination of strict aseptic technique, prophylactic antibiotics and good anaesthetic control during surgery remains crucial to reduce post-operative surgical infections.
Comparison of Basal-Bolus and Premixed Insulin Regimens in Hospitalized Patients With Type 2 Diabetes
Authors: Bellido Virginia , Suarez Lorena , Rodriguez Maria Galiana , Sanchez Cecilia , Dieguez Marta , Riestra Maria , Casal Florentino , Delgado Elias , Menendez Edelmiro , Umpierrez Guillermo E.
Published: October 2015

OBJECTIVE

Premixed insulin is a commonly prescribed formulation for the outpatient management of patients with type 2 diabetes. The safety and efficacy of premixed insulin formulations in the hospital setting is not known.

RESEARCH DESIGN AND METHODS

In a prospective, open-label trial, we randomized general medicine and surgery patients to receive a basal-bolus regimen with glargine once daily and glulisine before meals (n = 33) or premixed human insulin (30% regular insulin and 70% NPH insulin) twice daily (n = 39). Major outcomes included differences in daily blood glucose (BG) levels and frequency of hypoglycemic events (<70 mg/dL) between treatment groups.

RESULTS

At the first prespecified interim analysis, the study was stopped early because of an increased frequency of hypoglycemia >50% in patients treated with premixed human insulin. A total of 64% of patients treated with premixed insulin experienced one or more episodes of hypoglycemia compared with 24% in the basal-bolus group (P < 0.001). There were no differences in mean daily BG level after the first day of insulin treatment (175 ± 32 vs. 179 ± 43 mg/dL, P = 0.64) between groups. A BG target between 80 and 180 mg/dL before meals was achieved in 55.9% of BG readings in the basal-bolus group and 54.3% of BG readings in the premixed insulin group (P = 0.23). There was no difference in the length of hospital stay or mortality between treatment groups.

CONCLUSIONS

Inpatient treatment with premixed human insulin resulted in similar glycemic control but in significantly higher frequency of hypoglycemia compared with treatment with basal-bolus insulin regimen in hospitalized patients with diabetes.
Depressive Symptoms in Youth With Type 1 or Type 2 Diabetes: Results of the Pediatric Diabetes Consortium Screening Assessment of Depression in Diabetes Study
Authors: Silverstein Janet , Cheng Peiyao , Ruedy Katrina J. , Kollman Craig , Beck Roy W. , Klingensmith Georgeanna J. , Wood Jamie R. , Willi Steven , Bacha Fida , Lee Joyce , Cengiz Eda , Redondo Maria J. , Tamborlane William V. ,   for the Pediatric Diabetes Consortium
Published: October 2015

OBJECTIVE

To evaluate the frequency of depressive symptoms and the diagnosis and management of depression in youth with type 1 diabetes (T1D) and type 2 diabetes (T2D) enrolled in the Pediatric Diabetes Consortium T1D and T2D registries.

RESEARCH DESIGN AND METHODS

The Children’s Depression Inventory (CDI) 2 Self-Report (Short) version was completed by 261 T1D and 339 T2D youth aged 10–17 years.

RESULTS

Symptoms of depression were identified in 13% of T1D and 22% of T2D (P = 0.007) participants; of these, only 4% of T1D and 9% of T2D youth were treated by a therapist within the prior 12 months. Depressive symptoms were associated with lower family income (P = 0.006) and obesity (P = 0.002) in T1D but not T2D youth.

CONCLUSIONS

Depressive symptoms are more frequent than diagnosed depression in youth with T1D or T2D. These results underscore the need for regular depression screening and appropriate referral for youth with diabetes.
Reply to Wiebe et al.
Authors: Boruch Robert F. , Rovine Michael J. , Perna Laura W. , Ruby Alan
Published: October 2015

The intent of our 2014 article titled “Moving Through MOOCs: Understanding the Progression of Users in MOOCs” was to present evidence and to stimulate evidence-based discussion about the progression of users through MOOCs. It is then a pleasure to respond to those who reacted to the article. Most attention in our response is given to the fit between questions that are asked and the limitations on data that are available to address them, and to the analytic strategies that one might adapt to understand the data and its implications.
Tissue engineering of the tympanic membrane using electrospun PEOT/PBT copolymer scaffolds
Authors: Danti Serena , Mota Carlos , D’alessandro Delfo , Trombi Luisa , Ricci Claudio , Redmond Sharon L. , De Vito Andrea , Pini Roberto , Dilley Rodney J. , Moroni Lorenzo , Berrettini Stefano
Published: October 2015

Objective:

Tissue engineering has recently been identified as a suitable tool to develop replacements for the tympanic membrane. This study aimed at investigating PEOT/PBT copolymer scaffolds obtained via electrospinning as potential eardrum substitutes using an in vitro approach.

Study design:

PEOT/PBT copolymer ultrafine fibre meshes were manufactured and characterized for morphology and pore features. The scaffolds were cultured with human mesenchymal stromal cells (MSCs) under a dynamic flow regimen to improve cell infiltration and viability. The expression of basic extracellular matrix molecules was evaluated and compared to that of the human eardrum. Finally, the interaction between human tympanic membrane keratinocytes and the scaffolds was investigated.

Results:

The electrospun scaffolds had a fibre diameter of 1.9 ± 0.9 μm, thickness of 220 ± 56 μm, and porosity of 80% ± 0.8%. The macroporous meshes were suitable for cell infiltration, since 83.3% of relative void volume was from pores of 3–300-μm size. Over a four week culture, the bioreactor always increased the viability of human MSCs in the scaffolds with respect to traditional multi-well plate cultures. Viability was best at two weeks in culture, so this time-point was selected for further morphological and histochemical analyses. In static cultures, the human MSCs interacted with the top surface of the fibrous scaffold, while in dynamic cultures they infiltrated the mesh up to 240-μm depth. Adherent human MSCs maintained a non-differentiated phenotype, as shown by a very low production of glycosaminoglycans and glycoproteins, which are conversely highly expressed in the eardrum connective tissue layer. Human tympanic membrane keratinocytes adhered to the scaffold surface and were viable after 48 h.

Conclusion:

Using electrospinning combined with bioreactor culture appeared an efficient approach to develop biohybrid eardrum replacements in vitro, suitable for re-epithelialization in vivo.
Oral Submucous Fibrosis: A Review Article on Etiopathogenesis
Authors: Tak J , Gupta N , Bali R
Published: October 2015

Areca quid chewing related oral mucosal lesions are potential hazard to a large population worldwide. Commercially freeze dried products such as pan masala, guthka and mawa have high concentration of areca nut per chew and appear to cause OSMF more rapidly than by self prepared conventional betel quid that contain smaller amounts of areca nut. The basic constituent of areca nut is either raw or dried or boiled or baked. Diverse agents including lime, tobacco, catechu, cloves, saffron and leaf of piper betel leaves may form a part of formulation. Many of the undesirable aspects of areca nut have been attributed to arecoline. These chemical appear to interfere with the molecular processes of deposition and or degradation of extracellular matrix molecules such as collagen, causing imbalance in the normal process. The most likely events that take place with regards to the above imbalance may be reduced phagocytosis of collagen by fibroblasts, up or down regulation of copper dependent enzyme lysyl oxidase, matrix metalloproteinases and tissue inhibitors of matrix metalloproteinases. It has been postulated that areca nut may also induce the development of the disease by increased levels of cytokines in the lamina propria. Current evidence implicates collagen related genes in susceptibility and pathogenesis of OSMF. The individual mechanisms operating at various stages of the disease- initial, intermediate and advanced–need further study in order to propose appropriate therapeutic interventions.Kathmandu University Medical Journal Vol.12(2) 2014: 153-156
Givat Rabi East. a New Middle Paleolithic Knapping Site in the Lower Galilee (Israel)
Authors: Ekshtain Ravid , Barzilai Omry , Inbar Moshe , Milevski Ianir , Ullman Micka
Published: October 2015

Givat Rabi Est est un affleurement de silex récemment découvert dans le centre de la Galilée, à proximité de plusieurs sites du Paléolithique moyen. Cet article présente le site et traite de l’utilisation d’un amas de déchets de taille du Paléolithique moyen, fouillée sur son bord oriental. Les résultats suggèrent que les déchets de taille sont probablement les vestiges d’un atelier moustérien. En comparaison avec le site d’atelier de Sde Ilan, situé à 15 km à l’est, où le silex à été extrait, à Givat Rabi Est les tailleurs ont acquis le silex par ramassage de blocs de silex qui ont été érodés in situ. L’assemblage lithique indique que les séquences de taille étaient initiées sur le site et que plusieurs méthodes de Levallois ont été utilisées. Par conséquent, nous suggérons que les assemblages lithiques qui ont été laissés à Givat Rabi Est représentent des activités de taille de plusieurs groupes, qui ont utilisé cet emplacement pendant le Paléolithique moyen. Une partie du matériau lithique était emportée en d’autres lieux (par exemple des grottes) pour continuer la séquence de taille. L’emplacement du site, tout comme les caractéristiques du débitage, laissent supposer que le site de Givat Rabi Est a pu être utilisé comme une source de silex pour la grotte de Qafzeh et peut-être pour d’autres grottes moustériennes.