bluuebunny/crossref_metadata_2025 huggingface dataset:
HydraJet Testing under Deep Well Conditions Defines New Requirements for Hard-Rock Perforating
Authors: Surjaatmadja Jim B. , Bailey Andrew , Sierra Silverio
Published: April 2009

The use of hydrajetting for perforating wells has been common since the sixties. During those early years, wells were relatively shallow and jetting success was consistently demonstrated. However, as wells were drilled to depths where rock formations were harder, performance of hydrajetting became less dependable because subsequent stimulation failures occurred more often from the lack of fracture initiation.

To help prevent this situation, a series of tests were performed to define new best practices for hydrajet perforating of rock under high ambient pressure. Various rocks were subjected to the tests that were conducted using different jetting pressures and abrasives. To better understand the jetting behavior, the mechanical characteristics (such as Young's Moduli, Poisson's Ratios, and compressive strengths) and chemical structures were also evaluated.

This paper discusses various tests results, and new constraints for jetting are defined and presented.
Pinpoint Fracturing Using a Multiple-Cutting Process
Authors: Houser Jessica , Hernandez Rafael
Published: April 2009

This case-history paper describes methods of perforating and fracturing with coiled tubing (CT) in the South Belridge Field of California. Techniques presented in this paper allowed the operating company (OC) to fracture-stimulate multiple zones in a single trip of the CT. Each zone received fracturing treatments individually without affecting other zones. By employing a procedure developed for use in the wells of the Belridge Field that involves performing two perforating cuts (using a 5-ft tool twice) in one hydrajetting operation, using 90-mesh sand and allowing decreased circulation overflush volumes, the OC was able to double the number of perforations in each producing interval, thereby increasing the area of formation treated and the amount of proppant placed in each interval while decreasing total volume of fluid used per treatment stage.

Procedures presented are applicable in production areas where multiple pay zones require fracture stimulation. Without application of pinpoint-stimulation techniques, stimulation fluid applied to a long interval will likely enter the zone presenting the least resistance and consequently bypass other zones without stimulating them at all. Operators have solved this problem in the past by using the perf-and-plug technique, which is effective, but also slow and expensive. The CT-conveyed, pinpoint stimulation (PPS) process reduces the duration of the fracturing process for all zones from days to hours. The prominent feature of the PPS process is hydrajet-assisted fracturing (HJAF) using wellbore sand plugs immediately placed after each frac stage (Gilbert et al. 2005; Hejl et al. 2006, East et al. 2008).

Before switching to pinpoint stimulation by CT, the OC treated its wells by conventional fracturing methods, usually treating three zones with each frac stage. Interval lengths were from 150 to 250 ft, and the treating-fluid stage volume was large to deliver enough proppant for the large interval. The pumping rate was about 40 bbl/min to accommodate the interval length. However, radioactive-tracer logs run after all the frac operations showed some intervals were not treated with frac sand. With the HJAF process, the OC was able to treat each interval equally, with assurance that each pay zone was fracture-stimulated. Treating deeper zones was easier than before, and higher proppant concentrations and increased proppant volumes could then be placed in each interval. The use of the 90-mesh sand (instead of 20/40 size) for the perforating cuts allowed decreased volumes of fluid to be circulated. This method greatly reduced stage pump times and therefore, has reduced fracture-stimulation costs for the OC.
CO2 Flooding the Elm Coulee Field
Authors: Shoaib Shehbaz , Hoffman B. Todd
Published: April 2009

The Elm Coulee Field has extremely low permeability for an oil reservoir (0.01 – 0.04 md), which has caused an unconventional approach to its development by drilling long horizontal wells and massively fracturing them. The primary recovery factor, however, remains very low, around 5-10%. Significant reserves are available for post-primary production, yet the low permeability value restricts the choices available; for example, water flooding results in low injectivity. CO2 flooding may prove to be the most suitable option; however, the performance of CO2 flooding in this type of reservoir is not well understood. Using this field as an example, this paper presents the effects of CO2 flooding horizontal wells in a tight oil reservoir where hydraulic fractures provide the main path for fluid flow.

To analyze the impact of CO2 flooding in the Elm Coulee Field, a sector of the field is selected for reservoir modeling. The sector is two miles by two miles and consists of six, single-lateral horizontal wells. Two different reservoir models are built for the sector: a primary recovery and a CO2 flood model. They are used to determine the additional recovery due to a CO2 flood. Furthermore, the CO2 flood model is executed with different scenarios to determine the best well locations and injection schemes.

The models demonstrate that CO2 flooding horizontal wells in Elm Coulee Field increases production. Comparison of vertical and horizontal injection techniques indicates continuous horizontal CO2 injection is more efficient; it yields higher injection rates, and it is also beneficial for long-term recovery. Focusing on horizontal injection, the best scenario involves the practice of drilling new injectors along with converting existing producers to injection wells. In order to satisfy production requirements, production wells can be drilled such that there is an injector between two producers. This type of arrangement on horizontal injection increases the field recovery factor by 16 % after eighteen years of injection. The increase associated with single-well cyclic injection treatment is only 1 %; but in the absence of continuous CO2 supply, this method may be applicable for increasing recovery from reservoirs similar to Elm Coulee Field.

This research project demonstrates the technical aspects of CO2 injection in the context of Elm Coulee Field, while the economics are not considered. Developing a CO2 flood in this field appears feasible; however, the price of oil and the cost of drilling or converting wells will affect which, if any, is the best option.
Production Analysis of Multiply Fractured Horizontal Wells
Authors: Gilbert J. V. , Barree R. D.
Published: April 2009

Fracturing of horizontal wells is responsible for increasing rates and reserves from many reservoirs. Determining the optimum number of treatments, spacing, and eventual completion efficiency is critical to the success of a horizontal well development. This paper details the production analysis techniques required to evaluate the completion efficiency of multiply-fractured horizontal wells. Analytically modeled responses will be compared with actual horizontal well data to verify the technique.
Horizontal, Near-Wellbore Stress Effects on Fracture Initiation
Authors: Roundtree Russell , Eberhard Mike , Barree Robert
Published: April 2009

Throughout the past decade, the number of horizontal wells drilled in the United States has continued to increase. Several fields currently being developed are only economical with the application of horizontal wells. One such area where this is the case is in the Bakken formation in the Williston Basin. In the Bakken, operators have used a variety of different completion methods ranging from multilateral, openhole wellbores to single lateral cemented liners. Regardless of the completion method, hydraulic fracturing is required for increased oil recovery. In the past two years, most operators have started to converge on running uncemented liners with external packers as the preferred completion method. The purpose of the external packers is to compartmentalize the wellbore for more efficient fracture stimulation, as demonstrated by Miller (2008).

As this type of completion becomes more common, three key questions should be addressed: (1) how does the fracture initiate in an open-annulus wellbore (transverse or longitudinal), (2) what is the affect of the packer type on the stress on the wellbore surrounding the packer, and (3) can any of this be used to help with fracture design, or does it even matter?

Finite-element modeling provides several advantages for modeling the different physical characteristics and responses for a system with very different sensitivities across the scale of the model. In the cases considered in this paper, the edge of the wellbore must be finely modeled to take into account the hoop stresses developed as a result of removing the rock volume from the original stress state. This is further complicated by the effects of orientation of the wellbore relative to the maximum and minimum horizontal stress and of different packers placed in the wellbore for isolation between stages.

Conclusions on fracture-initiation behavior based on typical wellbore geometries, physical-rock properties, in-situ stress scenarios, and common packers are presented in this paper.
Do Texas groundwater conservation districts matter?
Authors: Foster J. R.
Published: April 2009

Texas faces a number of issues in an attempt to balance the water needs of a growing population while at the same time trying to conserve its water resources. Some of these issues include infrastructure improvements and provision of new supplies, changing patterns of use, water marketing and aquifer depletion. With aquifers providing 60% of all the water used in Texas, protecting and keeping these sources viable in the future is a key priority in addressing the state's water issues. With the state's emphasis on local control and the existence of between 80 and 90 groundwater districts state-wide, this research seeks to answer the question “Do groundwater districts in the State of Texas make a difference in groundwater depletion?” We use panel data from a set of 8,110 observations in a fixed effects regression to help us answer this question. We find evidence to suggest that groundwater districts do make a difference. After taking into consideration a couple of potential threats to validity, we run our model on a per district basis and by groundwater management areas. We also run it on a per aquifer basis and compare results with recommendations in the 2007 Texas Water Plan as a reality check. If we successfully answer the question that districts do in fact matter, the next logical step is to investigate what it is that districts do that makes a difference.
An assessment of the willingness to pay for reliable water supply in NCT-Delhi
Authors: Nallathiga Ramakrishna
Published: April 2009

Water is increasingly becoming a scarcer commodity, particularly in large cities of developing countries. Drinking water is an important use of water which has been catered for by most of the local governments. However, it is provided with a varying degree of reliability and the cost of this is not known. Consumers would like to pay for a reliable water supply besides what they pay for the normal water supply (both quantity and quality of water supplied). This paper presents an application of the contingent valuation method (CVM) for estimating the value of reliable water supply in National Capital Territory (NCT) – Delhi. The study implications and the lessons accruing from it are also summarized.
Governance and management of irrigation systems
Authors: Palerm-Viqueira Jacinta
Published: April 2009

This article explores the argument that an analytical differentiation between governance and management of irrigation systems can be a useful tool; focussing on management type provides a new perspective. It is possible to distinguish between cases of self-governance where irrigators carry out all tasks with reference to local knowledge and the alternative extreme, consisting of cases of self-governance where all management is carried out by hired professional staff. Besides this, bureaucratic and technocratic management is found in irrigation systems with diverse loci of authority (state and self-governance). It is further proposed that; whereas the self-governance of irrigation systems appears not to be restricted by the size of the system, a non-bureaucratic management, without specialized staff will be restricted because of this factor. However, it is argued that governance and management interact in such a way that the decentralization of governance may act as a strategy for avoiding or reducing bureaucratic management.
Estimating demand for irrigation water in European Mediterranean countries through MCDM models
Authors: Berbel J. , Viaggi D. , Manos B.
Published: April 2009

This paper reports results from the European project WADI which evaluates the sustainability of the European irrigation sector under different policy scenarios. Results presented are based on the generation of farm level water demand curves through multicriteria mathematical programming models. The results are compared across regions and matched against a review of water pricing policies that were in place in various European Union member states and accession countries prior to the entering into force of the Water Framework Directive (WFD). The results emphasise the variability of behaviour of irrigated systems and the need for a more clear understanding of policy objectives before implementing any policy instrument. Once the objectives are clarified, economic models can contribute to understanding the appropriateness of different management strategies and to the effectiveness of different policy instruments.
Micro–macro linkages in institutional restructuring processes in the water sector: example of the operations management support project (OMS) in Jordan
Authors: Rothenberger Dieter , Meuss Marina , Stoll Uwe
Published: April 2009

The German Agency for Technical Cooperation (GTZ) has supported the Water Authority of Jordan (WAJ) since 1994 by the provision of assistance aimed at increasing the efficiency of the potable water supply and wastewater disposal services under the Operations Management Support (OMS) project.

Using OMS as an example, this article shows the links of the change processes at the utility and the sector level (micro–macro linkages) for the introduction of institutional changes within the Jordanian water sector. The support of OMS followed co-evolutionary thinking, that is, it supported the dynamics coming from the utility level and affecting the sector level as well as the feedback loops from sector level to utility level. On the utility level, OMS activities and the induced improvements are a technical base for wider reform processes. They facilitated the implementation of private sector participation, PSP, with better quality base data. The information systems which were introduced by the project also indicated the importance of structural changes on the sector level and the urgency of these reforms. And finally, the involvement of OMS staff on the utility level made them credible when offering advice about the sector level. Hence, the parallel support of activities on both levels provided a deeper awareness of the reform issues and contributed to the success of the sector reforms.
Antibacterial Activity and Anticorrosive Efficiency of Aqueous Methanolic Extract of Artemisia pallens (Asteraceae) and Its Major Constituent
Authors: Elango Adirajan , Nandi Debkumar , Vinayagam Jayaraman , Meyyappan Arumugam , Pal Churala , Dey Sumit , Giri Venkatachalam Sesha , Mukherjee Joydeep , Garai Subhadra , Jaisankar Parasuraman
Published: April 2009

An aqueous-methanolic [methanol:water (1:1)] extract of the whole plant of Artemisia pallens (Family: Asteraceae) has shown good antibacterial activity against Pseudomonas aeruginosa and Shigella flexneri at the concentration of 100 mg/mL. The activity-guided fractionation has led to isolation of compound 4-hydroxyphenyl-?-D-glucopyranoside (which is known as arbutin), as a major constituent and exhibited the same antibacterial activity at a concentration of 17 mg/mL. Both the crude extract and arbutin also showed 94% anticorrosive efficiency against mild steel in 1M HCl at concentration of 200 mg/L.
The Effect of Salary Caps in Professional Team Sports on Social Welfare
Authors: Dietl Helmut M , Lang Markus , Rathke Alexander
Published: April 2009

This paper provides a theoretical model of a team sports league and studies the welfare effect of salary caps. It shows that salary caps will increase competitive balance and decrease overall salary payments within the league. The resulting effect on social welfare is counter-intuitive and depends on the preference of fans for aggregate talent and for competitive balance. A salary cap that binds only for large-market clubs will increase social welfare if fans prefer aggregate talent despite the fact that the salary cap will result in lower aggregate talent. If fans prefer competitive balance, on the other hand, any binding salary cap will reduce social welfare.
Force Decay of Elastomeric Ligatures: Influence onUnloading Force Compared to Self-Ligation
Authors: Petersen Alan , Rosenstein Sheldon , Kim Ki Beom , Israel Heidi
Published: April 2009

Objective: To compare elastomeric ligatures (EL) vs self-ligating (SL) brackets in terms of their effects on the unloading force of a 0.014-inch CuNiTi aligning wire.

Materials and Methods: By simulating the alignment of a lingually malposed canine and using a full-arch design, three ligation methods—SL, EL, and “relaxed” elastomeric ligature (REL)— were tested with 30 wires per group. Each test was conducted in a dry field within a Plexiglas case at 35 ± 2°C. Eleven brackets were affixed from first molar to first molar site on a steel plate with a space created at the location of the left canine. The wire was deflected 3 mm then was unloaded at a speed of 2 mm per minute. Data were gathered from four points along the unloading plot generated during each test and then were compared by using the Kruskal-Wallis one-way analysis of variance. Mann-Whitney tests were used to compare combinations of groups.

Results: Wires ligated with EL and REL produced an average unloading force equal to 56% and 88%, respectively, of the same wire in an SL bracket.

Conclusions: The unloading forces produced by a wire after force decay of the elastomers are not statistically different from the forces present in self-ligating systems.
Effects of the Taper Shape, Dual-Thread, and Length on the Mechanical Properties of Mini-Implants
Authors: Kim Young-Kyun , Kim Yoon-Ji , Yun Pil-Young , Kim Jong-Wan
Published: April 2009

Objective: To analyze the mechanical effects of the length and the various shapes such as cylindrical shape, taper shape, and dual-thread shape on the insertion and removal torque of mini-implants.

Materials and Methods: Mini-implants (diameter 1.6 mm and length 6 mm and 8 mm) consisting of cylindrical, taper, and dual-thread groups were inserted and removed in Sawbones while measuring the torque and time. Mechanical analysis was done of maximum insertion torque (MIT), maximum removal torque (MRT), torque ratio (TR; MRT/MIT), insertion angular momentum (IAM), removal angular momentum (RAM), and time of MIT. Measurements were statistically evaluated to analyze any differences of shapes and lengths.

Results: The cylindrical shape had the lowest MIT and MRT in each length. Although taper shape showed the highest MIT in each length, dual-thread shape showed significantly higher MRT, TR, and RAM in each length (P < .05). Dual-thread groups showed a gentle increase of insertion torque and a gentle decrease of removal torque in contrast to the other shape groups. However, it had higher IAM and time of MIT. The long length group showed significantly higher measurements except for TR.

Conclusions: Dual-thread shape provided better mechanical stability with high removal torque on the broad range than other shapes. However, dual-thread shape may need improvement for reducing the long insertion time to decrease the stress to the surrounding tissue.
Effects of CPP-ACP Paste on the Shear Bond Strength of Orthodontic Brackets
Authors: Xiaojun Ding , Jing Lu , Xuehua Guo , Hong Ruan , Youcheng Yu , Zhangyu Gu , Sun Jian
Published: April 2009

Objective: To evaluate the effect of casein phosphopeptide–amorphous calcium phosphate (CPP-ACP) paste on shear bond strength and debonding failure modes of orthodontic brackets.

Materials and Methods: Freshly extracted premolars were randomly divided into four groups (n =18) as follows: in groups 1 and 3, the enamel was treated with a solution of CPP-ACP dissolved in artificial saliva; groups 2 and 4 served as controls, and the enamel was treated with artificial saliva. After conventional acid etching, in groups 1 and 2, brackets were bonded using a light-cured bonding system (Blugloo); while in groups 3 and 4, brackets were bonded using a conventional bonding system (Unite Bonding Adhesive). Bonded specimens were subjected to thermal cycling for 1000 cycles before debonding procedures. After debonding, teeth and brackets were examined under a stereomicroscope at 10× magnification to determine whether any adhesive remained, in accordance with the adhesive remnant index. The acid-etched enamel surfaces were also observed using scanning electron microscopy after treatment with and without CPP-ACP paste.

Results: The shear bond strengths of group 1 were significantly higher than those seen in group 2 (P < .01). There was no significant difference in the shear bond strengths of groups 3 and 4 (P > .05). Scanning electron microscopic observation showed that the pretreated enamel surface was rougher than that of the control surface after acid etching.

Conclusion: The use of CPP-ACP can be considered as an alternative prophylactic application in orthodontic practice since it did not compromise bracket bond strength.
Lip Vermilion Profile Patterns and Corresponding Dentoskeletal Forms in Female Adults
Authors: Tanikawa Chihiro , Nakamura Kayoko , Yagi Masakuzu , Takada Kenji
Published: April 2009

Objectives: To objectively classify shapes of the human lip vermilion in the lateral view, and to examine whether any morphologic characteristics of dentoskeletal patterns are specific to each classified lip profile pattern.

Materials and Methods: Pretreatment, lateral facial photographs of 234 Japanese women were selected. Investigators with expert knowledge of the anatomic traits of the lip vermilion in the lateral view extracted from images of the face a 13-dimensional feature vector that represented lip vermilion profile shapes. The vector quantization technique was applied to the feature vectors to mathematically optimize the number of lip vermilion profile patterns. Dentoskeletal patterns that corresponded to each classified lip shape were compared statistically.

Results: Seven patterns were found, and differences between patterns were notably maximized by the flatness of the anterior portion of the lip vermilion for the upper and lower lip, the position of the most protruded point of the lip vermilion, lip fissure inclination, and differences between the horizontal positions of the upper and lower lip vermilions. The dentoskeletal forms showed significant differences between classified lip vermilion profile patterns (P < .01).

Conclusions: (1) Vector quantization revealed that classifying lip vermilion profiles into seven representative patterns was optimal for maximizing differences in the configuration of the lip vermilion. (2) Lip vermilion profile shapes were found to be associated with horizontal lengths of the anterior cranial base, horizontal/vertical positions, inclination and length of the mandible, and horizontal positions and labio-lingual inclinations of the upper and lower incisors.
Stimulation of Bone Formation by Dietary Boron in an Orthopedically Expanded Suture in Rabbits
Authors: Uysal Tancan , Ustdal Ayca , Sonmez Mehmet Fatih , Ozturk Figen
Published: April 2009

Objective: To evaluate the effects of dietary boron on bone regeneration in rabbits in response to expansion of the midpalatal suture during different retention periods.

Materials and Methods: Twenty-eight 12-week-old New Zealand white male rabbits were separated into four equal groups: group 1 (B+10) and group 2 (B−10) had retention periods of 10 days with or without boron intake, respectively. Group 3 (B+20, with boron) and group 4 (B−20, without boron) were retained for 20 days. All groups had a 5-day expansion period. For both B+ groups, boron was prepared in distilled water and given to the rabbits during their (1) nursery phase (40 days), (2) expansion phase, and (3) retention period at a dosage of 3 mg/kg daily by oral gavage. Bone regeneration in the midpalatal suture was evaluated by a bone histomorphometric method, and the mineralized area (Md.Ar), fibrosis area (Fb.Ar), mineralized area/fibrosis area (Md.Ar/Fb.Ar), bone area (B.Ar) and osteoblast number (N.Ob) parameters were evaluated.

Results: Statistical analysis showed significant differences between groups for all investigated measurements. Md.Ar (P < .01), Md.Ar/Fb.Ar (P < .001), B.Ar (P < .01), and N.Ob (P < .01) parameters were increased and Fb.Ar (P < .01) was decreased in groups B+10 and B+20. No significant differences were observed during an additional 10-day retention period in all groups (P < .05).

Conclusions: Boron has a positive effect on the early phase of bone regeneration of the midpalatal suture in response to expansion and may be beneficial in routine maxillary expansion procedures.
Elevated MBL Concentrations Are Not an Indication of Association Between the MBL2 Gene and Type 1 Diabetes or Diabetic Nephropathy
Authors: Kaunisto Mari A. , Sjölind Lisa , Sallinen Riitta , Pettersson-Fernholm Kim , Saraheimo Markku , Fröjdö Sara , Forsblom Carol , Fagerudd Johan , Hansen Troels K. , Flyvbjerg Allan , Wessman Maija , Groop Per-Henrik ,   for the FinnDiane Study Group
Published: April 2009

OBJECTIVE

Mannose-binding lectin (MBL) is an essential component of the acute-phase immune response and may thus play a role in the pathogenesis of type 1 diabetes and diabetic nephropathy. The serum concentration of MBL is mainly genetically determined, and elevated concentrations have been associated with both type 1 diabetes and diabetic nephropathy. Previous genetic studies have not been conclusive due to the small number of patients and polymorphisms studied. We investigated whether MBL2 polymorphisms are associated with type 1 diabetes or diabetic nephropathy and whether patients with nephropathy have elevated MBL concentrations as indicated previously. Furthermore, we studied the association between MBL2 polymorphisms and MBL concentration.

RESEARCH DESIGN AND METHODS

We genotyped 20 MBL2 single nucleotide polymorphisms (SNPs) in a large, well-characterized Finnish case-control sample consisting of 1,297 patients with type 1 diabetes with or without nephropathy and 701 nondiabetic individuals. The serum concentration of MBL was available for 1,064 patients.

RESULTS

We found that 19 SNPs were associated with the MBL concentration (P = 3 × 10−81–7 × 10−4). MBL concentrations were higher in patients with macroalbuminuria compared with patients without nephropathy even when the patients were stratified by the MBL2 genotypic background in accordance with previous studies. However, no evidence of association between any of the SNPs or their haplotype combinations and type 1 diabetes or diabetic nephropathy was observed.

CONCLUSIONS

Although most of the MBL2 SNPs studied were associated with the MBL concentration, no common variations (neither single SNPs nor their haplotype combinations) confer risk of type 1 diabetes or diabetic nephropathy.
Butyrate Improves Insulin Sensitivity and Increases Energy Expenditure in Mice
Authors: Gao Zhanguo , Yin Jun , Zhang Jin , Ward Robert E. , Martin Roy J. , Lefevre Michael , Cefalu William T. , Ye Jianping
Published: April 2009

OBJECTIVE

We examined the role of butyric acid, a short-chain fatty acid formed by fermentation in the large intestine, in the regulation of insulin sensitivity in mice fed a high-fat diet.

RESEARCH DESIGN AND METHODS

In dietary-obese C57BL/6J mice, sodium butyrate was administrated through diet supplementation at 5% wt/wt in the high-fat diet. Insulin sensitivity was examined with insulin tolerance testing and homeostasis model assessment for insulin resistance. Energy metabolism was monitored in a metabolic chamber. Mitochondrial function was investigated in brown adipocytes and skeletal muscle in the mice.

RESULTS

On the high-fat diet, supplementation of butyrate prevented development of insulin resistance and obesity in C57BL/6 mice. Fasting blood glucose, fasting insulin, and insulin tolerance were all preserved in the treated mice. Body fat content was maintained at 10% without a reduction in food intake. Adaptive thermogenesis and fatty acid oxidation were enhanced. An increase in mitochondrial function and biogenesis was observed in skeletal muscle and brown fat. The type I fiber was enriched in skeletal muscle. Peroxisome proliferator–activated receptor-γ coactivator-1α expression was elevated at mRNA and protein levels. AMP kinase and p38 activities were elevated. In the obese mice, supplementation of butyrate led to an increase in insulin sensitivity and a reduction in adiposity.

CONCLUSIONS

Dietary supplementation of butyrate can prevent and treat diet-induced insulin resistance in mouse. The mechanism of butyrate action is related to promotion of energy expenditure and induction of mitochondria function.
Metabolic Syndrome and Diabetes, Alone and in Combination, as Predictors of Cardiovascular Disease Mortality Among Men
Authors: Church Timothy S. , Thompson Angela M. , Katzmarzyk Peter T. , Sui Xuemei , Johannsen Neil , Earnest Conrad P. , Blair Steven N.
Published: April 2009

OBJECTIVE

To examine cardiovascular disease (CVD) mortality risk in men with diabetes only, metabolic syndrome only, and concurrent metabolic syndrome and diabetes.

RESEARCH DESIGN AND METHODS

We examined CVD mortality risk by metabolic syndrome and diabetes status in men from the Aerobics Center Longitudinal Study (ACLS) (mean ± SD age 45.1 ± 10.2 years). Participants were categorized as having neither diabetes nor metabolic syndrome (n = 23,770), metabolic syndrome only (n = 8,780), diabetes only (n = 532), or both (n = 1,097). The duration of follow-up was 14.6 ± 7.0 years with a total of 483,079 person-years of exposure and 1,085 CVD deaths.

RESULTS

Age-, examination year–, and smoking-adjusted CVD death rates (per 1,000 man-years) in men with neither metabolic syndrome nor diabetes, metabolic syndrome only, diabetes only, and both were 1.9, 3.3, 5.5, and 6.5, respectively. CVD mortality was higher in men with metabolic syndrome only (hazard ratio 1.8 [95% CI 1.5–2.0]), diabetes only (2.9 [2.1–4.0]), and both (3.4 [2.8–4.2]) compared with men with neither. The presence of metabolic syndrome was not associated (1.2 [0.8–1.7]) with higher CVD mortality risk in individuals with diabetes. In contrast, the presence of diabetes substantially increased (2.1 [1.7–2.6]) CVD mortality risk in individuals with metabolic syndrome.

CONCLUSIONS

The presence of diabetes was associated with a threefold higher CVD mortality risk, and metabolic syndrome status did not modify this risk. Our findings support the fact that physicians should be aggressive in using CVD risk–reducing therapies in all diabetic patients regardless of metabolic syndrome status.
Treatment With the Human Once-Weekly Glucagon-Like Peptide-1 Analog Taspoglutide in Combination With Metformin Improves Glycemic Control and Lowers Body Weight in Patients With Type 2 Diabetes Inadequately Controlled With Metformin Alone
Authors: Nauck Michael A. , Ratner Robert E. , Kapitza Christoph , Berria Rachele , Boldrin Mark , Balena Raffaella
Published: April 2009

OBJECTIVE

To evaluate the efficacy and safety of taspoglutide (R1583/BIM51077), a human once-weekly glucagon-like peptide-1 analog, in patients with type 2 diabetes inadequately controlled with metformin.

RESEARCH DESIGN AND METHODS

Type 2 diabetic (n = 306) patients who failed to obtain glycemic control (A1C 7–9.5%) despite 1,500 mg metformin daily were randomly assigned to 8 weeks of double-blind subcutaneous treatment with placebo or taspoglutide, either 5, 10, or 20 mg once weekly or 10 or 20 mg once every 2 weeks, and followed for 4 additional weeks. All patients received their previously established dose of metformin throughout the study. Glycemic control was assessed by change in A1C (percent) from baseline.

RESULTS

Significantly greater (P < 0.0001) reductions in A1C from a mean ± SD baseline of 7.9 ± 0.7% were observed in all taspoglutide groups compared with placebo after 8 weeks of treatment: –1.0 ± 0.1% (5 mg once weekly), –1.2 ± 0.1% (10 mg once weekly), –1.2 ± 0.1% (20 mg once weekly), –0.9 ± 0.1% (10 mg Q2W), and –1.0 ± 0.1% (20 mg Q2W) vs. –0.2 ± 0.1% with placebo. After 8 weeks, body weight loss was significantly greater in the 10 mg (–2.1 ± 0.3 kg, P = 0.0035 vs. placebo) and 20 mg (–2.8 ± 0.3 kg, P < 0.0001) once-weekly groups and the 20 mg once every 2 weeks (–1.9 ± 0.3 kg, P = 0.0083) group than with placebo (–0.8 ± 0.3 kg). The most common adverse event was dose-dependent, transient, mild-to-moderate nausea; the incidence of hypoglycemia was very low.

CONCLUSIONS

Taspoglutide used in combination with metformin significantly improves fasting and postprandial glucose control and induces weight loss, with a favorable tolerability profile.
Cognition in the Early Stage of Type 2 Diabetes
Authors: Ruis Carla , Biessels Geert Jan , Gorter Kees J. , van den Donk Maureen , Kappelle L. Jaap , Rutten Guy E.H.M.
Published: April 2009

OBJECTIVE

Type 2 diabetes is known to be associated with decrements in memory and executive functions and information-processing speed. It is less clear, however, at which stage of diabetes these cognitive decrements develop and how they progress over time. In this study, we investigated cognitive functioning of patients with recent screen-detected type 2 diabetes, thus providing insight into the nature and severity of cognitive decrements in the early stage of the disease. Possible risk factors were also addressed.

RESEARCH DESIGN AND METHODS

Included in this study were 183 diabetic patients from a previously established study cohort and 69 control subjects. A full neuropsychological assessment, addressing six cognitive domains, was made for each participant. Raw test scores were standardized into z scores per domain and compared between the groups. Possible risk factors for cognitive decrements were examined with multivariate linear regression.

RESULTS

Relative to scores for the control group, mean z scores were between 0.01 and 0.2 lower in the diabetic group across all domains, but after adjustment for differences in IQ between patients and control subjects, only memory performance was significantly reduced (mean difference −0.15 [95% CI −0.28 to −0.03]). A history of macrovascular disease and current smoking were significant determinants of slower information-processing speed in patients with diabetes.

CONCLUSIONS

This study shows that modest cognitive decrements are already present at the early stage of type 2 diabetes. A history of macrovascular disease and smoking are significant risk factors for some early decrements.
The Second-Meal Phenomenon in Type 2 Diabetes
Authors: Jovanovic Ana , Gerrard Jean , Taylor Roy
Published: April 2009

OBJECTIVE

In health, the rise in glucose after lunch is less if breakfast is eaten. We evaluated the second-meal effect in type 2 diabetes.

RESEARCH DESIGN AND METHODS

Metabolic changes after lunch in eight obese type 2 diabetic subjects were compared on 3 days: breakfast eaten, no breakfast, and no breakfast but intravenous arginine 1 h before lunch.

RESULTS

Despite comparable insulin levels, the rise in plasma glucose after lunch was considerably less if breakfast had been eaten (0.68 ± 1.49 vs. 12.32 ± 1.73 vs. 7.88 ± 1.03 mmol · h−1 · l−1; P < 0.0001). Arginine administration almost halved the lunch rise in plasma glucose (12.32 ± 1.73 vs. 7.88 ± 1.03 mmol · h−1 · l−1). The plasma free fatty acid concentration at lunchtime directly related to plasma glucose rise after lunch (r = 0.67, P = 0.0005).

CONCLUSIONS

The second-meal effect is preserved in type 2 diabetes. Premeal administration of a nonglucose insulin secretagogue results in halving the postprandial glucose rise and has therapeutic potential.
Secular Trends in Diabetes-Related Preventable Hospitalizations in the United States, 1998–2006
Authors: Wang Jing , Imai Kumiko , Engelgau Michael M. , Geiss Linda S. , Wen Christina , Zhang Ping
Published: April 2009

OBJECTIVE

To examine secular trends in diabetes-related preventable hospitalizations among adults with diabetes in the U.S. from 1998 to 2006.

RESEARCH DESIGN AND METHODS

We used nationally representative data from the National Inpatient Sample to identify diabetes-related preventable hospitalizations. Based on the Agency for Healthcare Research and Quality's Prevention Quality Indicators, we considered that hospitalizations associated with the following four conditions were preventable: uncontrolled diabetes, short-term complications, long-term complications, and lower-extremity amputations. Estimates of the number of adults with diabetes were obtained from the National Health Interview Survey. Rates of hospitalizations among adults with diabetes were derived and tested for trends.

RESULTS

Age-adjusted rates for overall diabetes-related preventable hospitalizations per 100 adults with diabetes declined 27%, from 5.2 to 3.8 during 1998–2006 (Ptrend < 0.01). This rate decreased significantly for all but not for short-term complication (58% for uncontrolled diabetes, 37% for lower-extremity amputations, 23% for long-term complications [all P < 0.01], and 15% for the short-term complication [P = 0.18]). Stratified by age-group and condition, the decline was significant for all age-condition groups (all P < 0.05) except short-term complications (P = 0.33) and long-term complications (P = 0.08) for the age-group 18–44 years. The decrease was significant for all sex-condition combination subgroups (all P < 0.01).

CONCLUSIONS

We found a decrease in diabetes-related preventable hospitalizations in the U.S. from 1998 to 2006. This trend could reflect improvements in quality of primary care for individuals with diabetes.
Association Between Circulating Soluble Receptor for Advanced Glycation End Products and Atherosclerosis
Authors: Lindsey Jason B. , de Lemos James A. , Cipollone Francesco , Ayers Colby R. , Rohatgi Anand , Morrow David A. , Khera Amit , McGuire Darren K.
Published: April 2009

OBJECTIVE

To determine the association between circulating soluble receptor for advanced glycation end products (sRAGE) and coronary atherosclerosis.

RESEARCH DESIGN AND METHODS

Using data from the Dallas Heart Study, a probability-based population sample, the association between plasma levels of sRAGE and coronary artery calcium (CAC) was assessed among 2,571 subjects with complete imaging and sRAGE data.

RESULTS

An inverse graded association was observed between sRAGE quartiles and CAC, with CAC prevalence of 28.5% in quartile 1 compared with 15.7% in quartile 4 (P < 0.0001). After multivariable adjustment, the associations between sRAGE levels in the first and second quartiles (versus fourth quartile) and CAC remained statistically significant (adjusted odds ratio 1.71 [95% CI 1.2–2.4] and 1.5 [1.0–2.1], respectively).

CONCLUSIONS

sRAGE is a novel biomarker that is inversely associated with coronary atherosclerosis. The role of sRAGE in the pathobiology of atherosclerosis and its potential prognostic and therapeutic implications warrant further investigation.
Plasma 25-Hydroxyvitamin D Concentration and Metabolic Syndrome Among Middle-Aged and Elderly Chinese Individuals
Authors: Lu Ling , Yu Zhijie , Pan An , Hu Frank B. , Franco Oscar H. , Li Huaixing , Li Xiaoying , Yang Xilin , Chen Yan , Lin Xu
Published: April 2009

OBJECTIVE

To evaluate the association between 25-hydroxyvitamin D [25(OH)D] and metabolic syndrome in the Chinese population.

RESEARCH DESIGN AND METHODS

Plasma 25(OH)D was measured in a cross-sectional sample of 1,443 men and 1,819 women aged 50–70 years from Beijing and Shanghai. Metabolic syndrome was defined according to the updated National Cholesterol Education Program Adult Treatment Panel III criteria for Asian Americans. Fasting plasma glucose, insulin, lipid profile, A1C, and inflammatory markers were measured.

RESULTS

The geometric mean of plasma 25(OH)D was 40.4 nmol/l, and percentages of vitamin D deficiency [25(OH)D <50 nmol/l] and insufficiency [50 ≤ 25(OH)D <75 nmol/l] were 69.2 and 24.4%, respectively. Compared with the highest 25(OH)D quintile (≥57.7 nmol/l), the odds ratio for metabolic syndrome in the lowest quintile (≤28.7 nmol/l) was 1.52 (95% CI 1.17–1.98, Ptrend = 0.0002) after multiple adjustment. Significant inverse associations also existed between 25(OH)D and individual metabolic syndrome components plus A1C. Moreover, we observed significant inverse associations of 25(OH)D with fasting insulin and the insulin resistance index (homeostasis model assessment of insulin resistance [HOMA-IR]) in overweight and obese individuals (BMI ≥24 kg/m2) but not in their normal-weight counterparts (test for interaction: P = 0.0363 and 0.0187 for insulin and HOMA-IR, respectively).

CONCLUSIONS

Vitamin D deficiency is common in the middle-aged and elderly Chinese population, and a low 25(OH)D level is significantly associated with an increased risk of having metabolic syndrome and insulin resistance. Prospective studies and randomized clinical trials are warranted to determine the role of 25(OH)D in the development of metabolic syndrome and related metabolic diseases.
Serum Uric Acid Levels Improve Prediction of Incident Type 2 Diabetes in Individuals With Impaired Fasting Glucose
Authors: Kramer Caroline Kaercher , von Mühlen Denise , Jassal Simerjot Kaur , Barrett-Connor Elizabeth
Published: April 2009

OBJECTIVE

To determine whether serum uric acid predicts incident type 2 diabetes by glucose tolerance status in older community-dwelling adults.

RESEARCH DESIGN AND METHODS

Participants without diabetes at baseline were evaluated for incident type 2 diabetes 13 years later. Baseline glucose tolerance status was defined as normoglycemia, impaired fasting glucose, and impaired postchallenge glucose tolerance.

RESULTS

A total of 566 participants were included (mean age 63.3 ± 8.6 years; 41% men). Regression models adjusted for age, sex, BMI, diuretic use, and estimated glomerular filtration rate showed that for each 1 mg/dl increment in uric acid levels, incident type 2 diabetes risk increased by ∼60%. When analyses were stratified by glucose status, uric acid levels independently predicted incident type 2 diabetes among participants who had impaired fasting glucose (odds ratio 1.75, 95% CI 1.1–2.9, P = 0.02).

CONCLUSIONS

Uric acid may be a useful predictor of type 2 diabetes in older adults with impaired fasting glucose.
Male Predominance of Congenital Malformations in Infants of Women With Type 1 Diabetes
Authors: Evers Inge M. , de Valk Harold W. , Visser Gerard H.A.
Published: April 2009

OBJECTIVE

To investigate sex-related differences in maternal, perinatal, and neonatal outcome in type 1 diabetic pregnancies in the Netherlands.

RESEARCH DESIGN AND METHODS

This was a nationwide prospective cohort-based study. Logistic regression analysis was used to identify sex-specific risk factors for adverse pregnancy outcome.

RESULTS

A total of 323 type 1 diabetic pregnancies were included; 314 were ongoing after 24 weeks of gestation. There were eight twin pregnancies and one triplet, resulting in 324 infants born after 24 weeks of gestation. Multiple logistic regression analysis showed that the occurrence of congenital malformations was independently associated with male newborns (OR 3.5 [95% CI 1.3–10.0]; P = 0.02).

CONCLUSIONS

The higher incidence of congenital malformations in infants of women with type 1 diabetes appears to be restricted to male infants only.
Comparision of beam data requirements for MLC commissioning on a TPS
Authors: Solaiappan Gopi , Singaravelu Ganesan , Prakasarao Aruna , Supe Sanjay
Published: April 2009

Comparision of beam data requirements for MLC commissioning on a TPS

The treatment planning system (TPS) has become a key element in the radiotherapy process with the introduction of computer tomography (CT) based 3D conformal treatment planning. Commissioning of a MLC on a TPS either for conformal radiotherapy or intensity modulated radiation therapy (IMRT) requires beam data to be generated on a linear accelerator. Most of the TPS require these beam data to be generated with routine collimator jaws. However some TPS demand the data to be provided for MLC shaped fields. This prompted us to investigate whether beam data with jaws differ than that with MLC and whether the jaw based beam data would suffice for the commissioning of a MLC on a TPS.

Beam data like percentage depth dose (PDD), cross beam profiles and output factors was acquired for jaws and MLC defined square fields for 6, 10 and 23 MV photon beams. Percentage depth dose and cross beam profiles were acquired with a radiation field analyzer RFA-200, CC13-S ion chambers with active volume of 0.13 cm3 and OmniPro-Accept software from Scanditronix-Wellhofer. A Medtec-TG51 water tank with Max-4000 electrometer and 0.6 cc PTW ionization chamber and a mini phantom from Standard Imaging was utilized for output measurements for millennium-120 MLC (Varian Medical Systems) and SRS diode detector (Scanditronix-Wellhofer) of 0.6 mm diameter of active area and 0.3 mm of active volume thickness for micro-MLC (BrainLab).

The difference in PDD in the build-up region for millennium MLC was ±1.0% for 6 MV photons. For 10 MV photons the PDD difference was within ±4.0%. The difference in PDD for 23 MV photons ranged from 0% to 40.0%. PDD difference from build-up depth to about 28 cm was within ±1.0%. Difference in PDD crossed ±1.0% at 30 cm depth for 6 MV photons. The difference in PDD in the build-up region for mMLC was ±8.0% for 6 MV photons. For the smallest field size studied with micro-MLC i.e. 0.6 × 0.6 cm2 difference in PDD was more than ±1.0% in the build-up region and beyond a depth of 8.0 cm. The profiles for jaws and MLC agreed within the umbra region. However in the penumbra region small differences in doses were observed. The collimator scatter factor (Sc), phantom scatter factor (Sp) and output factor values for MLC were different that those for jaws.

The differences in beam characteristics could have implication for intensity modulated radiation therapy and stereotactic radiosurgery in terms of dose in the build up region, exit dose, dose to the planning target volume (PTV) and organ at risk (OAR). Impact of these dosimetric differences between jaw and MLC needs to be further studied in terms of dose volume histograms for PTV and OAR and its further impact on tumor control probability (TCP) and normal tissue complication probability (NTCP).