bluuebunny/crossref_metadata_2025 huggingface dataset:
Increased Matrix Metalloproteinase-9 Predicts Poor Wound Healing in Diabetic Foot Ulcers
Authors: Liu Yu , Min Danqing , Bolton Thyra , Nubé Vanessa , Twigg Stephen M. , Yue Dennis K. , McLennan Susan V.
Published: October 2008

OBJECTIVE—We studied the relationships of diabetic ulcer wound fluid matrix metalloproteinases (MMPs), tissue inhibitors of metalloproteinases (TIMPs), and transforming growth factor-ß1 (TGF-ß1) with wound healing rate.

RESEARCH DESIGN AND METHODS—The ulcers were cleansed to remove exudates, and wound fluids were collected for analysis of MMP-2 and -9, TIMP-1, and TGF-ß1.

RESULTS—At presentation, MMP-9 and the MMP-9–to–TIMP-1 ratio correlated inversely with the wound healing rate at 28 days (P < 0.001). MMP-9 and the MMP-9–to–TIMP-1 ratio were lower in the 23 patients who achieved complete healing at 12 weeks versus the 39 who did not. The pro–MMP-9 concentration was predictive of healing within 12 weeks. Addition of cutoffs for TIMP-1 (>480 pg/ml) and TGF-ß (>115 pg/ml) further improved its predictive power (area under the curve 0.94).

CONCLUSIONS—These findings suggest that a milieu with high MMP-9 may be indicative of inflammation and poor wound healing. Measurements of MMP-9, TIMP-1, and TGF-ß in wound fluid may help to identify ulcers at risk of poor healing.
Physical Activity May Facilitate Diabetes Prevention in Adolescents
Authors: Thomas Amy S. , Greene Lori F. , Ard Jamy D. , Oster Robert A. , Darnell Betty E. , Gower Barbara A.
Published: October 2008

OBJECTIVE—The aim of this study was to examine the association of physical activity with glucose tolerance and resting energy expenditure (REE) among adolescents.

RESEARCH DESIGN AND METHODS—Subjects were 32 male and female adolescents aged 12–18 years. Intravenous glucose tolerance (Kg) and REE were assessed under inpatient conditions after an overnight fast. Kg was determined as the inverse slope of time versus (ln) glucose over minutes 8–19 of an intravenous glucose tolerance test. Physical activity was assessed over 8 days using accelerometry (counts per minute).

RESULTS—In multiple linear regression analysis, Kg was positively associated with total physical activity (TPA), moderate physical activity (MPA), and 5-min bouts of MPA. Similarly, REE was positively associated with TPA, MPA, and 5-min bouts of MPA.

CONCLUSIONS—In this population, physical activity was positively related to both glucose tolerance and REE. These results suggest that moderate activity may be beneficial in the prevention of diabetes in adolescent populations both through promoting efficient glucose disposal and through increasing energy expenditure.
Insulin Gene Mutations as Cause of Diabetes in Children Negative for Five Type 1 Diabetes Autoantibodies
Authors: Bonfanti Riccardo , Colombo Carlo , Nocerino Valentina , Massa Ornella , Lampasona Vito , Iafusco Dario , Viscardi Matteo , Chiumello Giuseppe , Meschi Franco , Barbetti Fabrizio
Published: October 2008

OBJECTIVE—Heterozygous, gain-of-function mutations of the insulin gene can cause permanent diabetes with onset ranging from the neonatal period through adulthood. The aim of our study was to screen for the insulin gene in patients who had been clinically classified as type 1 diabetic but who tested negative for type 1 diabetes autoantibodies.

RESEARCH DESIGN AND METHODS—We reviewed the clinical records of 326 patients with the diagnosis of type 1 diabetes and identified seven probands who had diabetes in isolation and were negative for five type 1 diabetes autoantibodies. We sequenced the INS gene in these seven patients.

RESULTS—In two patients whose diabetes onset had been at 2 years 10 months of age and at 6 years 8 months of age, respectively, we identified the mutation GB8S and a novel mutation in the preproinsulin signal peptide (ASignal23S).

CONCLUSIONS—Insulin gene mutations are rare in absolute terms in patients classified as type 1 diabetic (0.6%) but can be identified after a thorough screening of type 1 diabetes autoantibodies.
Biophysical Correlates of Cognition Among Depressed and Nondepressed Type 2 Diabetic Patients
Authors: Elderkin-Thompson Virginia , Hellemann Gerhard , Gupta Rakesh K. , Kumar Anand
Published: October 2008

OBJECTIVE—Caudate magnetization transfer (MT) ratios have indicated an abnormality in the macromolecular protein pool of diabetic patients. This study examined the relationship between MT ratios of the caudate and cognitive performance.

RESEARCH DESIGN AND METHODS—Diabetic patients, diabetic and depressed patients, and healthy comparison subjects completed magnetic resonance imaging and a neuropsychological battery. Magnetization transfer ratios of caudate and three comparison regions were computed. The neuropsychological battery was aggregated into a global index of cognitive function and correlated with MT ratios.

RESULTS—MT ratios of the caudate correlated with cognitive performance, and the correlations were stronger among diabetic patients than healthy control subjects. Comorbid depression increased the strength of the correlation compared with diabetes alone. Comparison regions showed no evidence of a diabetes effect on cognition.

CONCLUSIONS—One mechanism precipitating cognitive loss during diabetes appears to be associated with cellular changes occurring in the macromolecular protein pool of the caudate.
Adult Metabolic Syndrome and Impaired Glucose Tolerance Are Associated With Different Patterns of BMI Gain During Infancy
Authors: Fall Caroline H.D. , Sachdev Harshpal Singh , Osmond Clive , Lakshmy Ramakrishnan , Biswas Sushant Dey , Prabhakaran Dorairaj , Tandon Nikhil , Ramji Siddharth , Reddy K. Srinath , Barker David J.P. , Bhargava Santosh K.
Published: October 2008

OBJECTIVE—The purpose of this study was to describe patterns of infant, childhood, and adolescent BMI and weight associated with adult metabolic risk factors for cardiovascular disease.

RESEARCH DESIGN AND METHODS—We measured waist circumference, blood pressure, glucose, insulin and lipid concentrations, and the prevalence of metabolic syndrome (National Cholesterol Education Program Adult Treatment Panel III definition) in 1,492 men and women aged 26–32 years in Delhi, India, whose weight and height were recorded every 6 months throughout infancy (0–2 years), childhood (2–11 years), and adolescence (11 years–adult).

RESULTS—Men and women with metabolic syndrome (29% overall), any of its component features, or higher (greater than upper quartile) insulin resistance (homeostasis model assessment) had more rapid BMI or weight gain than the rest of the cohort throughout infancy, childhood, and adolescence. Glucose intolerance (impaired glucose tolerance or diabetes) was, like metabolic syndrome, associated with rapid BMI gain in childhood and adolescence but with lower BMI in infancy.

CONCLUSIONS—In this Indian population, patterns of infant BMI and weight gain differed for individuals who developed metabolic syndrome (rapid gain) compared with those who developed glucose intolerance (low infant BMI). Rapid BMI gain during childhood and adolescence was a risk factor for both disorders.
Differential Effects of Two Isoenergetic Meals Rich in Saturated or Monounsaturated Fat on Endothelial Function in Subjects With Type 2 Diabetes
Authors: Tentolouris Nicholas , Arapostathi Christina , Perrea Despoina , Kyriaki Despoina , Revenas Constantinos , Katsilambros Nicholas
Published: October 2008

OBJECTIVE—To examine the acute effects of consumption of monounsaturated (MUFAs) and saturated fatty acids (SAFAs) on endothelial function in subjects with type 2 diabetes.

RESEARCH DESIGN AND METHODS—A total of 33 participants were examined after consumption of two different isocaloric meals: one rich in MUFA and one rich in SAFA, in the form of extra-virgin olive oil and butter, respectively. Endothelial function was assessed by determination of flow-mediated dilatation (FMD).

RESULTS—FMD did not change significantly after the MUFA-rich meal but declined after the SAFA-rich meal. The FMD during the experiment, expressed as incremental area under the curve, increased after the MUFA-rich meal by 5.2 ± 2.5% and decreased after the SAFA-rich meal by 16.7 ± 6.0% (Δ = −11.5 ± 6.4%; P = 0.008).

CONCLUSIONS—Consumption of an SAFA-rich meal is harmful for the endothelium, while a MUFA-rich meal does not impair endothelial function in subjects with type 2 diabetes.
Improved Carbohydrate Metabolism After Bariatric Surgery Raises Antioxidized LDL Antibody Levels in Morbidly Obese Patients
Authors: Garrido-Sánchez Lourdes , García-Almeida Jose M. , García-Serrano Sara , Cardona Isabel , García-Arnes Juan , Soriguer Federico , Tinahones Francisco J. , García-Fuentes Eduardo
Published: October 2008

OBJECTIVE—Antioxidized LDL (anti-oxLDL) antibodies have recently been suggested to be protective against the development of diabetes. We measured the changes in anti-oxLDL antibody levels in the inverse situation of improvement in carbohydrate metabolism.

RESEARCH DESIGN AND METHODS—The study was undertaken in 73 morbidly obese individuals, 21 of whom had type 2 diabetes, before and 7 months after they underwent bariatric surgery and in 11 healthy, nonobese individuals. Measurements were made of the area under the curve of glucose (AUCGlu) by an intravenous glucose tolerance test and of oxidized LDL (oxLDL) and IgG and IgM anti-oxLDL antibodies.

RESULTS—The morbidly obese patients with diabetes had significantly higher levels of oxLDL compared with the morbidly obese patients with normal fasting glucose and the control subjects and significantly lower levels of IgM anti-oxLDL antibodies. An inverse correlation was found between the levels of oxLDL and IgM anti-oxLDL antibodies (r = −0.352, P = 0.012). Although the levels of IgG and IgM anti-oxLDL antibodies rose after surgery, this increase was only significant in the diabetic patients, who experienced an improvement in their metabolic profile. Different multiple linear regression models showed that the AUCGlu was the main factor explaining the behavior of the levels of oxLDL and anti-oxLDL antibodies.

CONCLUSIONS—We found a close association between carbohydrate metabolism and IgM anti-oxLDL antibodies, which were significantly reduced in the morbidly obese patients with diabetes. The improvement in carbohydrate metabolism after bariatric surgery led to a significant increase in the levels of IgG and IgM anti-oxLDL antibodies.
In Vivo Insulin Sensitivity and Secretion in Obese Youth
Authors: Bacha Fida , Gungor Neslihan , Lee SoJung , Arslanian Silva A.
Published: October 2008

OBJECTIVE—Impaired glucose tolerance (IGT) represents a pre-diabetic state. Controversy continues in regards to its pathophysiology. The aim of this study was to investigate the differences in insulin sensitivity (IS) and secretion in obese adolescents with IGT compared with those with normal glucose tolerance (NGT) and type 2 diabetes.

RESEARCH DESIGN AND METHODS—A total of 12 obese adolescents with NGT, 19 with IGT, and 17 with type 2 diabetes underwent evaluation of insulin sensitivity (3-h hyperinsulinemic [80mu/m2/min]–euglycemic clamp), first-phase insulin and second-phase insulin secretion (2-h hyperglycemic clamp), body composition, and abdominal adiposity. Glucose disposition index (GDI) was calculated as the product of first-phase insulin × insulin sensitivity.

RESULTS—Insulin-stimulated glucose disposal was significantly lower in subjects with type 2 diabetes compared with subjects with NGT and IGT, with no difference between the latter two. However, compared with youth with NGT, youth with IGT have significantly lower first-phase insulin and C-peptide levels and GDI (P = 0.012), whereas youth with type 2 diabetes have an additional defect in second-phase insulin. Fasting and 2-h glucose correlated with GDI (r = −0.68, P < 0.001 and r = −0.73, P < 0.001, respectively) and first-phase insulin but not with insulin sensitivity.

CONCLUSIONS—Compared with youth with NGT, obese adolescents with IGT have evidence of a β-cell defect manifested in impaired first-phase insulin secretion, with a more profound defect in type 2 diabetes involving both first- and second-phase insulin. GDI shows a significantly declining pattern: it is highest in NGT, intermediate in IGT, and lowest in type 2 diabetes. Such data suggest that measures to prevent progression or conversion from pre-diabetes to type 2 diabetes should target improvement in β-cell function.
A Randomized Trial of Low-Dose Aspirin in the Prevention of Clinical Type 2 Diabetes in Women
Authors: Pradhan Aruna D. , Cook Nancy R. , Manson JoAnn E. , Ridker Paul M. , Buring Julie E.
Published: October 2008

OBJECTIVE—Subclinical inflammation is linked with the development of type 2 diabetes, and epidemiologic data suggest that this association may be stronger in women. Although small clinical studies have shown a prominent hypoglycemic effect of short-term high-dose aspirin, no randomized trials have directly evaluated the efficacy of aspirin in diabetes prevention at doses acceptable for use in routine clinical practice. We evaluated whether chronic low-dose aspirin prevents the development of clinical diabetes among initially healthy American women.

RESEARCH DESIGN AND METHODS—Subjects were enrolled in the Women's Health Study, a 10-year randomized double-blind, placebo-controlled trial of aspirin and vitamin E for primary prevention of cardiovascular disease and cancer. Between 1992 and 1995, 38,716 women aged ≥45 years and free of clinical diabetes were randomly assigned to either low-dose aspirin or placebo (median follow-up 10.2 years). Documented clinical type 2 diabetes was prospectively evaluated throughout the trial.

RESULTS—Among women randomly assigned to receive aspirin (n = 19,326) or placebo (n = 19,390), there was no statistically significant difference in the incidence of type 2 diabetes. There were 849 cases of diabetes in the aspirin group and 847 in the placebo group (rate ratio 1.01 [95% CI 0.91–1.11]). Stratification by diabetes risk factors including age, BMI, family history of diabetes, physical activity, A1C, and high-sensitivity C-reactive protein did not support a modulating effect of these variables. Analyses accounting for treatment duration and adherence similarly found no beneficial effects.

CONCLUSIONS—These data suggest that long-term low-dose aspirin does not prevent the development of clinical type 2 diabetes in initially healthy women.
Quantitative Assessment of Early Diabetic Retinopathy Using Fractal Analysis
Authors: Cheung Ning , Donaghue Kim C. , Liew Gerald , Rogers Sophie L. , Wang Jie Jin , Lim Shueh-Wen , Jenkins Alicia J. , Hsu Wynne , Lee Mong Li , Wong Tien Y.
Published: October 2008

OBJECTIVE—Fractal analysis can quantify the geometric complexity of the retinal vascular branching pattern and may therefore offer a new method to quantify early diabetic microvascular damage. In this study, we examined the relationship between retinal fractal dimension and retinopathy in young individuals with type 1 diabetes.

RESEARCH DESIGN AND METHODS—We conducted a cross-sectional study of 729 patients with type 1 diabetes (aged 12–20 years) who had seven-field stereoscopic retinal photographs taken of both eyes. From these photographs, retinopathy was graded according to the modified Airlie House classification, and fractal dimension was quantified using a computer-based program following a standardized protocol.

RESULTS—In this study, 137 patients (18.8%) had diabetic retinopathy signs; of these, 105 had mild retinopathy. Median (interquartile range) retinal fractal dimension was 1.46214 (1.45023–1.47217). After adjustment for age, sex, diabetes duration, A1C, blood pressure, and total cholesterol, increasing retinal vascular fractal dimension was significantly associated with increasing odds of retinopathy (odds ratio 3.92 [95% CI 2.02–7.61] for fourth versus first quartile of fractal dimension). In multivariate analysis, each 0.01 increase in retinal vascular fractal dimension was associated with a nearly 40% increased odds of retinopathy (1.37 [1.21–1.56]). This association remained after additional adjustment for retinal vascular caliber.

CONCLUSIONS—Greater retinal fractal dimension, representing increased geometric complexity of the retinal vasculature, is independently associated with early diabetic retinopathy signs in type 1 diabetes. Fractal analysis of fundus photographs may allow quantitative measurement of early diabetic microvascular damage.
International Tables of Glycemic Index and Glycemic Load Values: 2008
Authors: Atkinson Fiona S. , Foster-Powell Kaye , Brand-Miller Jennie C.
Published: October 2008

OBJECTIVE—To systematically tabulate published and unpublished sources of reliable glycemic index (GI) values.

RESEARCH DESIGN AND METHODS—A literature search identified 205 articles published between 1981 and 2007. Unpublished data were also included where the data quality could be verified. The data were separated into two lists: the first representing more precise data derived from testing healthy subjects and the second primarily from individuals with impaired glucose metabolism.

RESULTS—The tables, which are available in the online-only appendix, list the GI of over 2,480 individual food items. Dairy products, legumes, and fruits were found to have a low GI. Breads, breakfast cereals, and rice, including whole grain, were available in both high and low GI versions. The correlation coefficient for 20 staple foods tested in both healthy and diabetic subjects was r = 0.94 (P < 0.001).

CONCLUSIONS—These tables improve the quality and quantity of GI data available for research and clinical practice.
Plasma Apolipoprotein CI and CIII Levels Are Associated With Increased Plasma Triglyceride Levels and Decreased Fat Mass in Men With the Metabolic Syndrome
Authors: van der Ham Rachel L.M. , Dehnavi Reza Alizadeh , Berbée Jimmy F.P. , Putter Hein , de Roos Albert , Romijn Johannes A. , Rensen Patrick C.N. , Tamsma Jouke T.
Published: October 2008

OBJECTIVE—To determine whether, in accordance with observations in mouse models, high concentrations of the lipoprotein lipase inhibitors apolipoprotein (Apo) CI and ApoCIII are associated with increased triglyceride concentrations and decreased fat mass in men with the metabolic syndrome.

RESEARCH DESIGN AND METHODS—Plasma ApoCI, ApoCIII, and triglyceride concentrations were measured in the postabsorptive state in 98 men with the metabolic syndrome. Subcutaneous and visceral fat areas were measured by 3T-magnetic resonance imaging.

RESULTS—Triglyceride concentrations were 49% higher, and the average visceral fat area was 26% lower (both P < 0.001), in subjects with high ApoCI and ApoCIII compared with low ApoCI and ApoCIII. Subjects with either high ApoCI or ApoCIII had 16% (P < 0.05) and 18% (P < 0.01) decreased visceral fat area, respectively.

CONCLUSIONS—High concentrations of ApoCI and ApoCIII are associated with increased triglycerides and decreased visceral fat mass in men with the metabolic syndrome. These findings translate mouse studies into human pathophysiology.
Serum Adipocyte Fatty Acid–Binding Protein Levels Are Associated With Nonalcoholic Fatty Liver Disease in Type 2 Diabetic Patients
Authors: Hyun Koh Jang , Goo Shin Young , Min Nam Soo , Young Lee Mi , Hee Chung Choon , Yel Shin Jang
Published: October 2008

OBJECTIVE—Adipocyte fatty acid–binding protein (A-FABP) is a major cytoplasmic protein in adipocytes and macrophages and is closely associated with metabolic syndrome, type 2 diabetes, and atherosclerosis. Here, we investigated whether A-FABP was associated with nonalcoholic fatty liver disease (NAFLD) in type 2 diabetes.

RESEARCH DESIGN AND METHODS—We enrolled 181 type 2 diabetic patients. Clinical and biochemical metabolic parameters were measured. The severity of NAFLD was measured by ultrasound. A-FABP, adiponectin, and retinol-binding protein-4 (RBP-4) were determined by enzyme-linked immunosorbent assay.

RESULTS—A-FABP levels, defined as more than a moderate degree of fatty liver compared with men, those without metabolic syndrome, and those without NAFLD, were higher in women, patients with metabolic syndrome, and patients with overt NAFLD, respectively. Adiponectin was decreased according to the severity of NAFLD, but RBP-4 showed no difference. Age- and sex-adjusted A-FABP showed positive correlations with BMI, waist-to-hip ratio, waist circumference, triglycerides, γ-glutamyltransferase, fasting insulin, homeostasis model assessment of insulin resistance (HOMA-IR), A1C, and C-reactive protein (CRP) but showed negative correlation with HDL cholesterol. The odds ratio (OR) for the risk of overt NAFLD with increasing levels of sex-specific A-FABP was significantly increased (OR 2.90 [95% CI 1.15–7.29] vs. 7.87 [3.20–19.38]). The OR in the highest tertile of A-FABP remained significant after adjustments for BMI, waist circumference, A1C, HDL cholesterol, triglycerides, HOMA-IR, CRP, and hepatic enzymes.

CONCLUSIONS—Our study demonstrates that serum A-FABP is significantly associated with NAFLD in type 2 diabetes, independent of BMI, waist circumference, HOMA-IR, A1C, triglycerides, HDL cholesterol, and CRP.
Influence of meteorological conditions on the concentration of NO2 and NOx in northwest Poland in relation to wind direction
Authors: Kalbarczyk Robert , Kalbarczyk Eliza
Published: October 2008

Influence of meteorological conditions on the concentration of NO2 and NOx in northwest Poland in relation to wind direction

The aim of the work was to assess the temporal distribution of NO2 and NOx concentration in relation to wind direction and to determine the effect of major meteorological elements on the size of NO2 and NOx concentration in northwest Poland. In the area of the research, in the period from 1st May 2005 to 30th April 2007 the highest average concentration of NO2 and NOx, both during cold and warm half-years, occurred with southeasterly wind, and the lowest with south-westerly wind for NO2 and with north-easterly wind for NOx. The highest determination coefficients and, at the same time, the smallest estimation errors for multiple regression equations, describing the dependence of the concentration of NO2 and NOx from meteorological elements, were obtained with westerly wind in the cold half-year and with south-westerly wind in the warm half-year.
Brackish water ecosystem restoration based on integrated water system design
Authors: Kuijper Marijn , de Louw Perry
Published: October 2008

Brackish water ecosystem restoration based on integrated water system design

Despite their current location within a primary agricultural area, most of the creek remnants in the Dutch clay polder areas have a high potential for recovery into healthy ecosystems. Like most areas in the Netherlands the clay polders are densely populated. Therefore multifunctional land use is encouraged and different types of land use coexist within small distances from each other. As a result water conflicts occur: agricultural land use requires deep groundwater levels and causes eutrophication by spreading nutrients into the water system, while existing ecosystems within and around the creek remnants need wetland conditions and low nutrient levels. Furthermore periods of high discharge cause flooding of arable land. Extreme measures like filling in ditches and increasing water levels are needed to achieve the water targets for wetlands around the creeks. On the other hand, the effects of these measures easily cause water logging in nearby agricultural areas. We introduce an integrated approach for the restoration of creek ecosystems. Both the complex interaction of groundwater, surface water and ecology and the limiting conditions imposed by adjacent agricultural land use, spatial developments and regulatory settings like the European Water Framework Directive are thereby taken into account. A highly integrated set of measures is proposed creating optimal conditions for both high agricultural production and flourishing creek ecosystems.
High temporal resolution monitoring in a wet grassland (Oxfordshire, UK) for estimation of evaporative loss
Authors: Mould David
Published: October 2008

High temporal resolution monitoring in a wet grassland (Oxfordshire, UK) for estimation of evaporative loss

A strong diurnal regime in water levels (maximum range 10 cm) was discovered by pressure transducers programmed to measure water levels at high frequency. The wetland site is a restored wet grassland floodplain in a clay basin. These water table fluctuations are used to estimate evaporative loss from the soil profile assuming constant head recovery, and compared to actual evaporation measurements derived from eddy correlation-energy budget methods. The former performed well on dry days with a strong diurnal regime, and information gained from high temporal resolution monitoring improved hydrological understanding of the wetland considerably.
FEMWATER flow model of waste soil bank from lignite open pit mine
Authors: Wiencław Edward , Koda Eugeniusz , Marek Zbigniew , Kaczarewski Tadeusz
Published: October 2008

FEMWATER flow model of waste soil bank from lignite open pit mine

The paper presents the example of numerical modelling of groundwater flow during dewatering of the TURÓW lignite open pit mine. The basis of numerical solution was the problem of groundwater flow described by Richard's equation, using 3-D finite elements method. The main purpose of the modelling carried out, taking into consideration this model, was the prediction of water logging of the waste soil bank and its surroundings. Modelling test results of the groundwater flow will be applied for extension of dewatering system and the design of monitoring system of potential threat of the waste soil bank stability, constructed in the close vicinity of lignite mine.
Airport Taxi-Out Prediction Using Approximate Dynamic Programming
Authors: Balakrishna Poornima , Ganesan Rajesh , Sherry Lance
Published: October 2008

Flight delay is one of the pressing problems that have far-reaching effects on society and the nation's economy. A primary cause of flight delay in the National Airspace System is high taxi-out times (time between gate push-back and wheels-off) at major airports. Accurate prediction of taxi-out time is needed to make downstream schedule adjustments and for better departure planning, which could mitigate delays, emissions, and congestion on the ground. However, accurate prediction of taxi-out time is difficult because of uncertainties associated with the dynamically changing airport operation. A novel stochastic approximation scheme based on reinforcement learning (RL) is presented for predicting taxi-out times in the presence of weather and other departure-related uncertainties. The prediction problem is cast in a probabilistic framework of stochastic dynamic programming and solved by using approximate dynamic programming approaches (particularly RL). The strengths of the method are that it is nonparametric, unlike regression models with fixed parameters, it is highly adaptable to the dynamic airport environment since it is learning based, it is scalable, it is inexpensive since it does not need highly sophisticated surface management systems, and it can effectively handle uncertainties because of the probabilistic framework. Taxi-out prediction performance was tested on data obtained from the FAA Aviation System Performance Metrics database on Detroit International and Washington Reagan National Airports. Results show that the root-mean-square prediction error calculated 15 min before gate departure time is on average 2.9 min for about 80% of the predicted flights.
Toward Time-Based Separation Rules for Landing Aircraft
Authors: Janic Milan
Published: October 2008

Aircraft landing on the same runway are potentially exposed to a similar wake vortex hazard, under either instrument meteorological conditions (IMC) or visual meteorological conditions (VMC) when the air traffic control (ATC) distance-based instrument flight rules (IFR) and visual flight rules (VFR) are applied, respectively. Since IFR are stricter than VFR, the runway landing capacity is lower under IMC than under VMC. Possibilities are investigated for introducing time-based ATC separation rules instead of the current distance-based ATC separation rules between landing aircraft as an option for increasing the runway landing capacity under IMC and consequently decreasing the existing gap between IFR and VFR capacity. A model for calculating the landing capacity of a single runway on the basis of ATC time-based separation rules was developed. In addition to these rules, which would be set up by using the current ATC distance-based separation rules and the advanced knowledge on the current and predicted behavior of the wake vortex influenced by the weather conditions, the model uses other inputs, such as the structure of fleet mix in terms of the proportion of particular aircraft categories, which are represented by their wake vortex parameters (the approach speed, wingspan, and weight), and the geometry of the approach corridor, which enables landing on a given runway. The model output is the matrix of the standardized time-based separation rules for different combinations of landing aircraft sequences, which would be applicable to both VMC and IMC, and the runway landing capacity calculated for combinations of the time-based separation rules depending on the current and predicted wake vortex characteristics and behavior. The model is applied to calculating the landing capacity of a single airport runway.
Determining Moisture Content of Soil Layers with Time Domain Reflectometry and Micromechanics
Authors: Lee Sang Ick , Zollinger Dan G. , Lytton Robert L.
Published: October 2008

Although the moisture condition of pavement sublayers can significantly affect pavement performance, accurate interpretation of in situ soil moisture measurements has been difficult to achieve because of the limitations of existing methods. Time domain reflectometry (TDR), originally developed to detect breaks or shorts in electrical conductors, has been used for measuring parameters related to the in situ soil moisture content. However, the apparent length method currently used to determine dielectric constant ignores other electrical properties of the conducting medium that may affect the interpretation of TDR trace to determine soil moisture. Furthermore, the existing methods for computing volumetric water content ignore the variations of dry density and determine the model parameters with assumption or regression analysis. These deficiencies can, in many cases, create a significant systematic error in the final determination of volumetric water content. To minimize these errors and improve the accuracy of moisture content estimate, a new three-step approach was proposed. The approach uses the transmission line equation to calculate the dielectric constant, conductivity, and reflectivity of a soil mixture. A micromechanics and self-consistent scheme was used to determine the volumetric moisture content and dry density on the basis of calibrated values of the solid and water dielectric constants. The system identification method was used iteratively to solve for dielectric parameters, soil moisture content, and dry density values. The validation of the new approach with ground-truth data indicated that the calculated errors were significantly less than those of existing method.
PROBLEMS PREVENTING AIR COMPANIES FROM EFFICIENT INVESTMENT ACTIVITIES / AVIAKOMPANIJŲ INVESTICINĖS VEIKLOS EFEKTYVUMO PROBLEMŲ PREVENCIJA
Authors: Arljukova Irina
Published: October 2008

The article deals with the problems of investment development of air companies. The author examines the aspects of modelling of investment solutions under conditions of developing aviation business, giving methods of modelling of demand, including those based on dynamics of macroeconomic indicators. The article contains the problems relating to assessment of macroeconomic risks, using models of assessment of discount rates. Variants of assessment of currency risks in the process of evaluation of efficiency of international investment solutions are analyzed as well. This article also deals with some problems relating to project financing. The aspect on necessity to take into account correlation between man's potentiality and equipment capacity in the process of development of investment activities of air companies is discussed as well.

Santrauka

Straipsnyje nagrinėjamos aviakompanijų investicijų plėtros problemos. Autorė tyrinėja investicinių
sprendimų modeliavimo aspektus aviacijos verslo plėtros sąlygomis. Pateikiami paklausos modeliavimo metodai, tarp kurių yra nagrinėjančių makroekonomikos rodiklių dinamiką. Straipsnyje aptariamos makroekonominės rizikos įvertinimo problemos taikant modelius, įvertinančius diskonto normą. Taip pat nagrinėjami valiutos rizikos variantai tarptautinių investicinių sprendimų efektyvumo įvertinimo proceso kontekste. Šiame straipsnyje taip pat gvildenamos kai kurios projekto finansavimo problemos. Diskutuojama, ar aviakompanijų investicijų plėtros procese būtina įvertinti tarpusavio ryšį tarp apsirūpinimo žmogiškaisiais ištekliais ir įranginiais.
TheNrfHCytochromecQuinol Dehydrogenase
Authors: Rodrigues Maria Luisa , Pereira Inês AC , Archer Margarida
Published: October 2008

NrfH is a membrane‐anchored tetraheme cytochromecthat oxidizes menaquinol and transfers electrons to the cytochromecnitrite reductase, NrfA. It belongs to a family of cytochromecquinol dehydogenases, known as theNapC/NirT family, which plays an important role in bacterial anaerobic respiration. Here, we describe the major structural and biochemical features of NrfH that has been isolated in the form of a native NrfHA complex from someProteobacteriaspecies. The notable heme coordination of NrfH, revealed uponDesulfovibrio vulgarisNrfHA structure determination, is discussed in light of primary structure analysis within the NrfH proteins and within the family of cytochromecquinol dehydogenases. Interestingly, NrfH shows a higher sequence variation than other members of the NapC/NirT family. The crystal structure of NrfHA bound to the HQNO inhibitor is also presented and analyzed together with inhibition studies.
Glutamate CarboxypeptidaseII
Authors: Mesters Jeroen R , Hilgenfeld Rolf
Published: October 2008

Glutamate carboxypeptidase II (GCP II) is a homodimeric, dinuclear zinc carboxypeptidase that catalyzes the cleavage of two endogenous substrates carryingL‐glutamate at the C‐terminal P1′ position, namelyN‐acetyl‐L‐aspartyl‐α‐L‐glutamate (α‐NAAG) and folylpoly‐γ‐L‐glutamate (folylpolyglutamate). Former synonyms for GCP II, a type‐II membrane glycoprotein that belongs to the transferrin receptor family of proteins, include prostate‐specific membrane antigen (PSMA), folylpoly‐γ‐glutamate carboxypeptidase (FGCP), andN‐acetylated α‐linked acidic dipeptidase (NAALADase). GCP II predominantly occurs in nearly all types of glial cells and is drastically overproduced in endothelial cells of tumor‐associated neovasculature and in prostate cancer tissue. The particular role of PSMA, a folylpolyglutamate hydrolase, in prostate cancer is poorly understood. In the brain, GCP II catalyzes the cleavage of the abundant neuropeptide α‐NAAG that acts as an agonist for the metabotropic (i.e. G‐protein‐coupled) glutamate receptor‐3 (mGluR3), and as a mixed agonist/antagonist forN‐methyl‐D‐aspartate (NMDA) receptors. The liberatedL‐glutamate acts as a downstream neurotransmitter that is excitotoxic at high concentrations, harming retina and brain. Accordingly, inhibitory compounds of GCP II have been shown to provide neuroprotection. In addition, they may prove useful, through the binding to PSMA, for the imaging and possible treatment of certain forms of cancer.
Nitrogenase: Recent Advances
Authors: Andrade Susana LA , Hu Yilin , Ribbe Markus W , Einsle Oliver
Published: October 2008

Nitrogenase catalyzes the reductive fixation of nitrogen from atmospheric N2for biological syntheses, and as such it constitutes the only enzyme known to be able to cleave the highly stable triple bond of the dinitrogen molecule. Structures are known of both component proteins of nitrogenase, the enzymatically active MoFe protein and its electron donor, the Fe protein. In spite of a wealth of biochemical and biophysical data on nitrogenase, the mechanistic details of its action remain poorly understood. This article provides an update on recent results in nitrogenase research, including the discovery of a central, light atom in the center of the FeMo cofactor, studies on substrate binding to the cofactor in mutant proteins, and novel aspects of complex formation between both component proteins. Particular emphasis is given to the significant progress made in understanding the biosynthesis of the complex metal clusters of the MoFe protein, the P‐cluster and the FeMo cofactor.
Particulate Methane Monooxygenase
Authors: Rosenzweig Amy C
Published: October 2008

Particulate methane monooxygenase (pMMO) catalyzes the oxidation of methane to methanol in methanotrophic bacteria. The 300‐kDa pMMO enzyme is a trimeric integral membrane protein, comprising three copies each of three subunits: pmoB, pmoA, and pmoC. Purified pMMO contains both copper and iron, although some of the iron may be due to heme contamination. The copper stoichiometry ranges from 2 to 15 copper ions per 100‐kDa pMMO protomer, depending on the enzyme source. EPR spectra of whole cells, membrane‐bound, and purified pMMO consistently indicate the presence of type 2 Cu(II). According to XAS data, both Cu(I) and Cu(II) are present. EXAFS data reveal the presence of oxygen/nitrogen ligands and a short CuCu interaction at 2.5 Å that increases to 2.6 Å upon chemical reduction. Crystal structures of pMMO from two organisms have been reported. A soluble region consisting of six cupredoxin‐like β‐barrel structures is supported by 15 transmembrane helices. Three different metal centers have been detected crystallographically: a highly conserved dinuclear copper center, a nonconserved mononuclear copper center, and a site that can be occupied by zinc or copper. Although the identity of the pMMO active site remains unknown, some information regarding the mechanism has been obtained from substrate studies and computational work.
TheCorAMg2+Channel
Authors: Maguire Michael E
Published: October 2008

The CorA Mg2+channel is present in about 50% of bacteria and many archaea. Its ubiquitous eukaryotic homolog is Mrs2, the mitochondrial Mg2+channel. Physiologically, CorA mediates the influx of Mg2+down its electrochemical gradient. It can also mediate the influx of Ni2+and Co2+but only at concentrations that are toxic to the cell. A subclass of the CorA superfamily in the bacteria mediates the efflux of Zn2+. The sequence analysis of the CorA superfamily shows a complete lack of homology to any other protein. The crystal structure of CorA confirms its unique nature. CorA is a homopentamer shaped like a funnel with the stem of the funnel within the membrane. Each monomer has two transmembrane segments at the C terminus. All prokaryotic CorA proteins have the same basic structure. A 250–290 amino acid cytosolic N‐terminal domain is followed by transmembrane segment 1, which is followed by a nine amino acid periplasmic loop. This loop is followed by the transmembrane segment 2. Neither transmembrane segment contains any charged amino acids. The C‐terminal cytosolic tail of CorA is almost always six amino acids in length and contains three or four arginine and/or lysine residues. In the structures currently available, the Mg2+‐conducting pore is formed completely by transmembrane segment 1. The cytosolic domain is formed of a seven‐stranded antiparallel β sheet flanked on both sides by three α helices (α1–3β1–7α4–6). This domain is followed by the 100‐Å‐long α7helix, which forms most of the inner face of the funnel and transmembrane segment 1. In the cytosolic domain, a Mg2+cation is bound between an aspartate residue in the α7helix of one monomer and the α3helix of the adjacent monomer, giving five bound Mg2+cations per channel. These bound ions seem poised to act as ‘sensors’ of intracellular Mg2+, and their dissociation from the channel is proposed to allow the monomers to rotate apart, thus opening the channel.
Detectable Trends in Hydroclimatical Variables During the Twentieth Century
Authors: Kundzewicz Zbigniew W
Published: October 2008

The twentieth century was a period of considerable climatic and nonclimatic change. The atmospheric concentration of greenhouse gases increased significantly, due to increased burning of fossil fuels and land‐use changes that reduce carbon sequestration. The long carbon dioxide record from Mauna Loa illustrates the man‐caused enhancement of the “greenhouse effect”, which resulted in an increase in global temperature of 0.74 °C over the last 100 years. In the Northern Hemisphere, the temperature increase during the twentieth century is likely to have been greater than for any other century in the last 1000 years. This has affected hydrological processes. Patterns of precipitation change are more spatially and temporally variable, but some regional regularities can be detected. The river runoff process, which is the most important for freshwater management, has not shown general, nor coherent, changes globally, because river runoff is an integrator of many climatic and nonclimatic factors. In a number of places, nonclimatic drivers can be demonstrated to have had a considerable influence on hydrological records.
Groundwater Monitoring Strategies
Authors: van Geer Frans C , Bierkens Marc FP , Broers Hans Peter
Published: October 2008

Monitoring of groundwater pressure heads and groundwater quality is an integral part of water management. This article focuses on strategies of spatial and temporal distribution of data collection. Other aspects of monitoring such as well construction, measurement equipment, and database management are not discussed. In order to design, optimize, and evaluate monitoring systems, many approaches are in use. Although it is impossible to complete, we attempt to provide an overview of approaches to the design of groundwater monitoring strategies. Rather than giving extensive mathematical descriptions, we discuss design approaches from a practical point of view: each design approach is introduced through a case study where attention is paid to the link between monitoring objective and monitoring network design.
Catchment Classification and Services—Toward a New Paradigm for Catchment Hydrology Driven by Societal Needs
Authors: Wagener Thorsten , Sivapalan Murugesu , McGlynn Brian
Published: October 2008

Hydrologists do not yet possess a generally accepted catchment classification system. This article presents a review of work done so far, and discusses a general framework for a catchment classification system considering variability in relevant characteristics, increasing human impacts on catchments, and the assumption that our climate is changing. We stress that any classification system should explicitly account for uncertainty and have predictive power, rather than just being descriptive. We also propose an extension to catchment classification with the inclusion of catchment services and disservices, which would explicitly link hydrology to current and future societal issues. We discuss a framework that describes catchment climate and form and maps these on catchment function (include partition, storage and release of water, energy and matter). Climate, form, and function can be described using indices, distributions, or even conceptual models; and uncertainty needs to be preserved in individual descriptors as well as in their mapping onto each other. Descriptors of catchment function are discussed as signatures of catchment behavior, which in turn are related to catchment services and disservices. This mapping ultimately provides predictive skill by constraining the expected function at ungauged locations, even under potential nonstationarity, through knowledge of form and/or climate. Establishing this framework would provide an organizing principle, create a common language, guide modeling and measurement efforts, provide constraints on predictions in ungauged basins, and allow estimates of environmental change impacts.
Overview of Receptor Interactions of Agonists and Antagonists
Authors: Kenakin Terry
Published: October 2008

Historically, the earliest methods used to quantitatively measure the fundamental properties of drugs (namely affinity and efficacy) employed isolated tissues, and it is in this realm that the null methods used to define “receptor pharmacology” were described. This unit describes these methods and their use to specifically classify agonists (through potency ratios and determination of relative affinities and efficacies) and antagonists (through analysis of surmountable and insurmountable antagonism) to yield estimates of potency. Different drugs can yield different behaviors in various tissues, so this unit is centered on a flow diagram to indicate the type of analysis appropriate for the behavior observed. For example, some agonists may be full agonists in some tissues and partial agonists in others, while some antagonists may demonstrate surmountable simple competitive antagonism in some tissues and insurmountable non‐competitive antagonism in others. Methods exist for determination of affinity and efficacy for all of these behaviors, and these are delineated in this unit.Curr. Protoc. Pharmacol. 42:4.1.1‐4.1.24. © 2008 by John Wiley & Sons, Inc.
Gastrointestinal Models: Intestinal Transit, Gastric Emptying, and Ulcerogenic Activity in the Rat
Authors: Guillaume Philippe , Provost Daniel , Lacroix Pierre
Published: October 2008

The protocols described in this unit are designed to assess the effects of substances on intestinal transit and gastric emptying and to evaluate their ulcerogenic potential on the stomach and duodenum of the rat. Examples of results obtained with atropine or morphine (intestinal transit), loperamide (gastric emptying), or indomethacin (ulcerogenic activity) used as reference substances are provided for illustrative purposes. Atropine and morphine clearly reduce intestinal transit. Atropine, morphine, and loperamide clearly reduce gastric emptying. Indomethacin shows a marked ulcerogenic potential. Curr. Protoc. Pharmacol. 42:5.3.1‐5.3.12. © 2008 by John Wiley & Sons, Inc.
Chemical Synthesis of Oligoribonucleotides with 2′‐O‐(2‐Cyanoethoxymethyl)‐Protected Phosphoramidites
Authors: Ohgi Tadaaki , Kitagawa Hidetoshi , Yano Junichi
Published: October 2008

An RNA synthetic method with 2‐cyanoethoxymethyl (CEM) as the 2′‐hydroxyl protecting group allows the synthesis of long oligoribonucleotides from CEM‐amidites with an efficiency and final purity comparable to that obtained in DNA synthesis. The CEM‐amidites give a high coupling efficiency, because the CEM group minimizes steric hindrance in the coupling reaction. The CEM group shows satisfactory stability under solid‐phase synthetic conditions, avoids the generation of asymmetric centers, and is easily cleaved to give the final product. This unit describes the synthesis of the four CEM‐amidites, the preparation of reagents, the solid‐phase synthesis of oligoribonucleotides on an automated DNA synthesizer, and their deprotection. Curr. Protoc. Nucleic Acid Chem. 34:2.15.1‐2.15.19. © 2008 by John Wiley & Sons, Inc.
RNA Intramolecular Dynamics by Single‐Molecule FRET
Authors: Hengesbach Martin , Kobitski Andrei , Voigts‐Hoffmann Felix , Frauer Carina , Nienhaus G. Ulrich , Helm Mark
Published: October 2008

Investigation of single RNA molecules using fluorescence resonance energy transfer (FRET) is a powerful approach to investigate dynamic and thermodynamic aspects of the folding process of a given RNA. Its application requires interdisciplinary work from the fields of chemistry, biochemistry, and physics. The present work gives detailed instructions on the synthesis of RNA molecules labeled with two fluorescent dyes interacting by FRET, as well as on their investigation by single‐molecule fluorescence spectroscopy. Curr. Protoc. Nucleic Acid Chem. 34:11.12.1‐11.12.22. © 2008 by John Wiley & Sons, Inc.