bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cabergoline and the risk of valvular lesions in endocrine disease.
Authors: Lancellotti Patrizio , Livadariu Elena , Markov Muriel , Daly Adrian F , Burlacu Maria-Cristina , Betea Daniela , Pierard Luc , Beckers Albert 
Published: May 2008

AimsThe cardiac valvular risk associated with lower exposure to cabergoline in common endocrine conditions such as hyperprolactinemia is unknown.Methods and resultsWe performed a cross-sectional, case–control echocardiographic study to assess the valvular status in 102 subjects receiving cabergoline for endocrine disorders and 51 matched control subjects. Cabergoline treatment ranged from 12 to 228 months, with a cumulative dose of 18–1718 mg. Valvular regurgitation was equally prevalent in both groups and was almost exclusively mild. Two cabergoline-treated subjects had moderate mitral regurgitation; there was no relationship between cabergoline dose and the presence or severity of mitral valve regurgitation (P=NS). Mitral valve tenting area was significantly greater in the cabergoline group when compared with the control subjects (P=0.03). Mitral valve leaflet thickening was observed in 5.9% of cabergoline-treated subjects; no relationship with the cumulative cabergoline dose was found. No patient had aortic or tricuspid valvular restriction.ConclusionNo significantly increased risk of clinically relevant cardiac valve disorders was found in subjects treated with long-term cabergoline therapy at the doses used in endocrine practice. While exposure to cabergoline appears to be safe during low-dose long-term therapy, an association with subclinical changes in mitral valve geometry cannot be completely excluded.
Dental Development of Chinese Children with Cleft Lip and Palate
Authors: Lai Moon Cheung , King Nigel M. , Wong Hai Ming 
Published: May 2008

Objective: To compare the dental development and rate of tooth development between children with and without cleft lip and palate. Patients: Age- and gender-matched pairs (231 in all) of southern Chinese children ages 3 to 12 years, with and without cleft lip and palate. Methods: Dental histories and radiographs were studied. From these, dental development was determined. Results: Of 2946 tooth pairs in the children with cleft lip and palate, 252 (8.6%) were found to be asymmetric, significantly (p < .001) more than the 63 of 3179 (2.0%) tooth pairs observed in the children without cleft lip and palate. The teeth with the highest frequency of asymmetry were the maxillary lateral incisors (38.1%). Differences in dental development on the cleft versus noncleft sides of children with unilateral cleft lip and palate were significant for both maxillary and mandibular teeth (p < .001 and p  =  .039, respectively). The mean delay in tooth formation of the children with cleft lip and palate was 4.4 months relative to the children without cleft lip and palate. The majority of the teeth in the cleft lip and palate group were delayed by one developmental stage. This happened in 40.0% of the maxillary teeth and 30.1% of the mandibular teeth. The delay in tooth formation increased as the number of missing teeth increased in the children with cleft lip and palate, although not significantly. Conclusions: This group of southern Chinese children with cleft lip and palate demonstrated a higher prevalence of asymmetric and delayed dental development than did their counterparts who did not have cleft lip and palate.
Biodegradation of Three Different Collagen Membranes in the Rat Calvarium: A Comparative Study
Authors: Moses Ofer , Vitrial Doron , Aboodi Guy , Sculean Anton , Tal Haim , Kozlovsky Avital , Artzi Zvi , Weinreb Miron , Nemcovsky Carlos E. 
Published: May 2008

Background: Collagen barrier membranes are commonly applied in periodontal and bone‐regenerative procedures. Membranes differ in their resorption pattern following implantation, thus influencing clinical outcome. The purpose of this study was to quantitatively evaluate the biodegradation of three different commercially available collagen membranes.Methods: Collagen membranes were cut into 5‐mm‐diameter disks and labeled with aminohexanoyl‐biotin‐N‐hydroxy‐succinimide ester. One membrane disk of each type (non‐cross‐linked [NCL], glutaraldehyde cross‐linked [GCL], and ribose cross‐linked [RCL]) was implanted on the calvaria of 20 Wistar rats. Block sections were retrieved after 2 days (baseline, two animals), 14 days (10 animals), or 28 days (eight animals). Decalcified histologic sections were stained with streptavidin horseradish peroxidase. Residual membrane thickness and area were measured. Statistical analysis consisted of analysis of variance (ANOVA) with repeated measures.Results: Statistically significant differences in the amount of residual membrane material were recorded within each membrane (among different time points) and among different membranes at the same time points (P <0.001). At 28 days, the least amount of residual collagen area, expressed as the percentage of baseline, was observed in the NCL group (13.9% ± 10.25%), followed by the GCL (24.7% ± 35.11%) and RCL (91.3% ± 10.35%) groups. Residual membrane thickness, expressed as the percentage of baseline thickness, presented a similar pattern (31% ± 16.55%, 37% ± 41.90%, and 94.1% ± 12.22%, respectively). ANOVA with repeated measures showed a significant interaction between membranes and time (P <0.001).Conclusions: The tested membranes differed in their degradation patterns and collagen contents. Membranes should be chosen for each clinical case according to the desired biodegradation characteristics.
Stromal‐Derived Factor‐1α (CXCL12) Levels Increase in Periodontal Disease
Authors: Havens Aaron M. , Chiu Evonne , Taba Mario , Wang Jincheng , Shiozawa Yusuke , Jung Younghun , Taichman L. Susan , D'Silva Nisha J. , Gopalakrishnan R. , Wang CunYu , Giannobile William V. , Taichman Russell S. 
Published: May 2008

Background: The CXC chemokine receptor 4 (CXCR4) and its ligand, stromal cell–derived factor‐1 (SDF‐1α or CXC chemokine ligand 12) are involved in the trafficking of leukocytes into and out of extravascular tissues. The purpose of this study was to determine whether SDF‐1α secreted by host cells plays a role in recruiting inflammatory cells into the periodontia during local inflammation.Methods: SDF‐1α levels were determined by enzyme‐linked immunosorbent assay in gingival crevicular fluid (GCF) of 24 individuals with periodontitis versus healthy individuals in tissue biopsies and in a preclinical rat model of Porphyromonas gingivalis lipopolysaccharide–induced experimental bone loss. Neutrophil chemotaxis assays were also used to evaluate whether SDF‐1α plays a role in the recruitment of host cells at periodontal lesions.Results: Subjects with periodontal disease had higher levels of SDF‐1α in their GCF compared to healthy subjects. Subjects with periodontal disease who underwent mechanical therapy demonstrated decreased levels of SDF‐1α. Immunohistologic staining showed that SDF‐1α and CXCR4 levels were elevated in samples obtained from periodontally compromised individuals. Similar results were observed in the rodent model. Neutrophil migration was enhanced in the presence of SDF‐1α, mimicking immune cell migration in periodontal lesions.Conclusions: SDF‐1α may be involved in the immune defense pathway activated during periodontal disease. Upon the development of diseased tissues, SDF‐1α levels increase and may recruit host defensive cells into sites of inflammation. These studies suggest that SDF‐1α may be a useful biomarker for the identification of periodontal disease progression.
Tissue‐Engineered Cultured Periosteum Used With Platelet‐Rich Plasma and Hydroxyapatite in Treating Human Osseous Defects
Authors: Yamamiya Kanoko , Okuda Kazuhiro , Kawase Tomoyuki , Hata Ken‐ichiro , Wolff Larry F. , Yoshie Hiromasa 
Published: May 2008

Background: The aim of the present controlled clinical study was to compare the clinical response of human cultured periosteum (HCP) sheets in combination with platelet‐rich plasma (PRP) and porous hydroxyapatite (HA) granules to a mixture of PRP and HA in the treatment of human infrabony periodontal defects.Methods: Thirty interproximal infrabony osseous defects in 30 healthy, non‐smoking subjects diagnosed with chronic periodontitis were included in this study. The subjects were randomly assigned to the test group (HCP sheets combined with PRP and HA) or the control group (PRP with HA). Clinical and radiographic measurements were made at baseline and the 12‐month post‐surgical evaluation.Results: Compared to baseline, the 12‐month results indicated that both treatment modalities resulted in statistically significant changes (P <0.01) in the gingival index, bleeding on probing, probing depth, clinical attachment level, and radiographic infrabony defect depth. Compared to the control group, the test group exhibited a statistically significantly more favorable change in clinical attachment gain (3.9 ± 1.6 mm versus 2.7 ± 1.3 mm; P <0.05), vertical relative attachment gain (83.5% ± 31.7% versus 55.0% ± 21.9%; P <0.05), and radiographic infrabony defect fill (4.9 ± 1.2 mm versus 3.2 ± 1.1 mm; P <0.01).Conclusions: Compared to PRP with HA, treatment with a combination of HCP sheets, PRP, and HA led to a significantly more favorable clinical improvement in infrabony periodontal defects. A factor likely contributing to these favorable clinical results is the presence of osteogenic cells in the HCP sheets, which provided greater regeneration potential.
Simultaneous Flapless Implant Placement and Peri‐Implant Defect Correction: An Experimental Pilot Study in Dogs
Authors: Jeong Seung‐Mi , Choi Byung‐Ho , Li Jingxu , Xuan Feng 
Published: May 2008

Background: Minimally invasive implant surgery allows clinicians to place implants in less time, without extensive flaps, and with less bleeding and postoperative discomfort. The purpose of this study was to evaluate a new surgical technique by which implants are inserted in a deficient alveolar ridge using a flapless technique simultaneously with a peri‐implant defect correction that is performed using a subperiosteal tunneling procedure.Methods: Bilateral, horizontal defects of the alveolar ridge were created in the mandibles of five mongrel dogs. After 3 months of healing, one implant was placed on each side of the mandible by a flapless procedure. The exposed threads of the implant on one side of the mandible were covered with a 1:1 autogenous bone/xenograft mixture using a subperiosteal tunneling technique. Four months later, biopsies of the implant sites were taken and prepared for ground sectioning and analysis.Results: All implants were well osseointegrated with the host bone. All of the peri‐implant defects at the test sites were covered with tissue that resembled bone. In all specimens, a mixture of bone, connective tissue, and residual bone particles was observed in the graft area. In the control sites, where no graft was used, none of the exposed threads on any implants were covered with new bone.Conclusion: This preliminary report indicates the potential use of a minimally invasive flapless technique as a substitute for a more invasive implant placement and ridge augmentation procedure.
Slip Calculation of Rotational Speed of Electrical Submersible Progressive Cavity Pumps
Authors: Zhou Desheng , Yuan Hong 
Published: April 2008

Abstract
Progressive cavity pumps (PCPs) are usually driven at surface through sucker rods. Due to the shear strength of sucker rods and the wear of the rod and tubing, the surface drive system limits its application in production rate and well depth, and in deviated and horizontal wells. Instead of using sucker rods to transmit driving torque from surface to pump, bottom driving PCP assembly sets electric submersible motors below PCP to drive the pump directly.
Electric submersible motors for PCP are three phase, squirrel cage, induction motors. Motor speed is controlled by its winding poles. Nominal motor speeds widely used are 3500 RPM for two-pole motors and 1700 RPM for four-pole motors. This paper presents simplified correlations by using the nominal motor speeds in the design and analysis of bottom driving PCP wells.
The simplified correlations do not account for the effect of motor speed slip. Actually, motor output speeds depend on loading power on the motor. Loading power is the power required by a PCP and its associated equipments to lift well fluid to surface. This paper presents the power consumption of each part in the bottom drive assembly, and the method of calculating motor slip from motor speed performance and calculated total required power. Also presented is the effect of frequency on motor speed. Finally presented are a model to design motor frequency with motor slip and an iteration algorithm to determine production rate at given frequency.
This paper clarifies the concepts of volumetric, brake, mechanical, hydraulic, and slip powers associated with PCP pumping. It also differentiated motor output nominal, no-load, and full-load speeds, and the output speeds at load factors, at standard frequency, and at design frequencies.
The Development of PCP Wells Troubleshooting Technique in Daqing Oilfield
Authors: He Liu , Yong Bi , Guochen Shi , Zhongguo Wang , Chaoyong Liu , Zhaoping Jiang 
Published: April 2008

Abstract
Trouble-shooting technique is an important part in artificial lift technology. Based on wave equation created by Gibbs from 1970s, dynamometer card method has been applied successfully in beam pumping well's trouble-shooting technique. As for PCP wells, there's no such the same parameter as beam pumping unit's dynamometer card which could indicate systems performance directly. In Daqing Oilfield, PCP trouble-shooting technique has been studied for more than ten years. Many methods were tried, such as operating current, effective power, rod string's operating torque and axial load, oscillation frequency, etc. Application indicated that, among all the above parameters, rod string's operating torque and axial load were the most effective ones to reflect PCP system's operating status to date. However, it was still difficult to give a clear description of a PCP system without the assistance of other parameters.
This paper overviewed the development history of PCP well's trouble-shooting technique in Daqing Oilfield. A comprehensive testing and trouble-shooting system was presented consisting of a loads sensor, a wireless signal processing system and the trouble-shooting software. The diagnose model was created on the basis of PCP wells' operating loads and the related production data base, which could distinguish ten types of operating status of PCP system. In the past few years, this system has been applied in more than 300 PCP wells in Daqing Oilfield. Although the compatibility of the model for different driving methods needs to be improved for a wider application（such as ASP flooding）, the system has been approved to be convenient and effective in water flooding and polymer flooding area which could apply a good reference for other issues.
The Mechanism of PCP Wells' Tubing and Rod Wear Issue in Polymer Flooding in Daqing Oil Field
Authors: He Liu , Xiaohan Pei , Baiqi Peng , Yu Hou , Yumei Wang , Guoqing Wang 
Published: April 2008

AbstractAlthough PCP technology has been used in Daqing Oilfield from 1980s, and the number of PCP wells in the whole oilfield has reached 2429 till September in 2006, it wasn’t applied in polymer flooding producers with displacement of over 150m3/d until 2004. However, the application of the high volume PCP systems has witnessed severe wear issue both in tubing and rods. Study indicated that, due to the great increment in displacement, the original design for smaller volume PCPs showed serious incompatibility with high volume PCP systems. For instance, bigger structure parameter resulted in higher rod oscillation in operation, and pipe string bending issue in high volume PCP was more popular than in lower ones using the traditional anchor. In addition, improper rod guiding also played an important role in wear of tubing and rod string.This paper analyzes the mechanism of tubing & rod wear for high volume PCPs in detail, and presents a series of harness treatments including: 1) optimizing pump selection method and operation parameter; 2) improving tubing anchoring method; and 3) optimizing rod string guiding method. Based on the above treatments, a set of optimum design model for high volume PCPs was created. Experiments and application showed that, using this optimum design model, tubing & rod wear failure rate was decreased sharply, and the operation performance was improved effectively for high volume PCPs in polymer flooding area.This study contributed a lot in not only improving the design method of traditional PCP technology, expanding the application scale of PCP system, but also presenting a good reference on how to squeeze the benefit of artificial lift technology in EOR stage.
The Successful Application of PCPs' Personalized Design in Hailar Oilfield
Authors: Gang Cao , Linghui He , Zhaomei Chen , Xuecheng Zheng , Qingbo Wang , Mingzhan Chen 
Published: April 2008

Abstract
Hailar Oilfield is a new block of Daqing Oilfield developed from the end of last century. In the beginning of the development, beam pumping unit was the only lifting method of the Oilfield. Due to the low pump efficiency and higher rod failure rate as well as the 2000m lift, beam pumping system was not as economic as other in blocks of Daqing Oilfield. As the result, PCP was put into production from 2005. Though all the four wells had a good performance with high pumping efficiency in the beginning, after several months' operation, rod strings suffered from severe oscillation and resulted in fatigue failures in a short period. Theoretical and experimental study indicated that, high working temperature (85 centigrade) and special oil characteristics caused much higher swelling degree of elastomer than in other blocks, which led to the increment of interference fit and friction force between rotor and stator.
In the initial application, although pump parameter and elastomer formula were adjusted before treatment to reduce the swelling effect, these adjustments didn’t take into effect as predicted. In that case, a personalized PCP design was brought forward which gave an integrated methodology for PCP application in Hailar Oilfield. In this design, all the lifting parts from surface to downhole equipments were considered as a whole system. FEM analysis was applied to make a detailed description of the pump for different operating temperature. Based on deeper adjustment of elastomer and pump's structure parameters, the optimum design of rod and other equipments were take into consideration as well. In the end of 2006, 4 new personalized design pumps were put into production. In the following year, despite of small oscillation in the first few days due to the influence of treatment water, all PCP systems performed stably with high efficiency.
Design of Progressive Cavity Pump Wells
Authors: Zhou Desheng , Yuan Hong 
Published: April 2008

Abstract
Progressive cavity pumps (PCPs) are a special type of rotary positive displacement pumps. PCP was first introduced in petroleum engineering as an artificial lift method in 1970's, and is becoming a popular lift tool for its advantages of broader applications, less maintenance, and higher efficiency. PCP performances have been studied for many years, but no published paper has discussed the relation of pump performances with well performances systematically.
This paper analyzes the system performances of PCP wells. Using nodal analysis method, the paper presents algorithms and procedures to design pump rotational speed and production rate from well inflow and outflow performances. For the effect of viscosity on pump volumetric slip, unlike traditional methods of trying to set up a general correlation for all PCP types, the paper propose a method to correct the effect of viscosity on each pump's catalog performance curves, and demonstrates how to use the corrected performances to design the pumping of viscous fluid.
By unfolding a PCP cavity and using simplified slot flow, this paper presents correlations to determine the critical pump intake pressures for filling pump cavity completely for Newtonian and non-Newtonian fluids.
The presented algorithms can be used not only to design a PCP well for pump rotational speed and production rate, but also to analyze the performance of a PCP pumping well. The presented correlations of the viscosity effect on slippage and the critical pump intake pressure are useful in PCP design and system analysis.
Computational Modeling of the Three-Dimensional Flow in a Metallic Stator Progressing Cavity Pump
Authors: Paladino Emilio E. , Lima João A. , Almeida Rairam F.C. , Assmann Benno W. 
Published: April 2008

Abstract
This work presents a novel computational model for the 3D flow in a rigid stator Progressing Cavity Pump (PCP), using an element based finite volume method, which includes the relative motion between rotor and stator. Usual flow models in PCPs consider a Poiseuille flow along the seal lines, i.e., along the positive clearance between cavities in order to predict the internal slip and then, the volumetric efficiency for different pressures, rotations and fluid viscosities. Furthermore, some attempts for more detailed models including computational solutions for the flow in simplified geometries can be encountered in literature. These approaches include, treating cavities as parallel plates or computing the flow between two static cavities, in all cases considering steady state flow, which is a strong hypothesis in this case. Nevertheless no models considering the solution for the full transient 3D Navier-Stokes equations and the relative motion between rotor and stator were encountered. The main challenge at this point was the imposition of the mesh motion and mesh generation process, mainly, because of the mesh quality control (element distortion) in regions near the seal lines, or in the clearance regions between rotor and stator.
The model developed is capable to predict accurately the volumetric efficiency and the viscous looses as well as provide detailed information of pressure and velocity fields inside this device. Furthermore, the present model could be used to predict the hydraulic performance of an elastomeric progressing cavity pump after stator wear or deformation and allow for the development of a computational model for the fluid-structure interaction which permits the analysis of the non-rigid stator case.
Site‐Specific Adsorption of 1,3‐Dinitrobenzene to Bacterial Surfaces: A Mechanism of n–π Electron‐Donor‐Acceptor Interactions
Authors: Qu Xiaolei , Xiao Lin , Zhu Dongqiang 
Published: May 2008

AbstractSurface and subsurface contamination with nitroaromatic compounds (NACs) has drawn considerable attention, and biosorption may play an important role in the fate and transport of these compounds in the environment. We studied the sorption of polar 1,3‐dinitrobenzene (DNB) as a representative NAC and 2,6‐dichlorobenzonitrile and nonpolar phenanthrene and 1,2,4,5‐tetrachlorobenzene from the aqueous phase to two common bacteria, gram‐negative Escherichia coli and gram‐positive Bacillus subtilis. Sorption of DNB is highly nonlinear and is well described by the Langmuir model and shows the highest capacity among all tested solutes (up to 2.4% of E. coli biomass and 7.6% of B. subtilis biomass by weight) despite the lowest solute hydrophobicity. These results indicate that strong specific sorptive interactions exist between DNB and bacterial surfaces. We propose a mechanism of n–π electron‐donor‐acceptor interactions between the oxygen electron pairs of deprotonated carboxyl groups (electron donors) of bacterial surfaces and DNB (electron acceptor). Biosorption of DNB increases with deprotonation of functional groups as pH increases, which rules out hydrophobic effects and H‐bonding as major sorption driving forces because they are both favored by protonation of functional groups as pH decreases.