bluuebunny/crossref_metadata_2025_split huggingface dataset:
Statistical properties of extragalactic H2O maser sources
Authors: Jiang-Shui Zhang , Christian Henkel 
Published: January 2008

AbstractRecently, with the development of sensitive maser receiver and wide-band spectrometer, maser emission were detected toward more and more galaxies. 69 galaxies beyond the Magellanic Clouds has been reported with H2O maser emission (to 2006.12). The statistical properties of the sample of extragalactic H2O masers are not well explored. Here we collect observation data of all these detected extragalactic H2O maser sources and give a statistical analysis to investigate the statistical properties of the sample.
OH megamasers as extragalactic diagnostics
Authors: Pihlström Ylva M. 
Published: January 2008

AbstractLuminous, extragalactic OH masers are excellent tracers of merger triggered, intense star formation in Ultra Luminous Infrared Galaxies (ULIRGs). As such, they are tracers of high density regions in the centers of active galaxies. From high resolution imaging of the 1667 MHz emission in a small sample of OH megamaser galaxies, the general consensus is that most of the maser emission arises in thick, circumnuclear structures. Here we summarize the current work on OH megamasers, and present the preliminary results on VLA observations of the 1720 MHz satellite line in III Zw 35, Mrk 231 and Arp 220. We also briefly mention ongoing work on investigating the nature of the high molecular gas density environment in a sample of ULIRGs, using CO (J=3–2) observations. A subset of the ULIRG sample harbors OH megamaser emission, and is therefore suited for comparing gas properties between ULIRGs with and without OH megamaser emission.
A compact starburst ring traced by clumpy OH megamaser emission
Authors: Parra Rodgrigo , Conway John E. , Elitzur Moshe , Pihlström Ylva M. 
Published: January 2008

AbstractWe model the OH megamaser emission from the luminous infrared galaxy IIIZw35 as arising from a narrow rotating starburst ring of radius 22 pc enclosing a mass of 7×106M⊙. We show how both the compact and apparently diffuse maser emission from this ring can arise from a single phase of unsaturated maser clouds amplifying background radio continuum. The masering clouds are estimated to have a diameter of <0.7 pc and internal velocity dispersion of ∽20 kms−1. We find that the clouds are neither self-gravitating nor pressure confined, and they could be magnetically confined or freely expanding. Their dispersal lifetimes may set the vertical thickness of the ring. For an estimated internal density of 3×103cm−3, cloud masses are of order 24M⊙. The observed spectral features and velocity gradients indicate that the clouds must be outflowing and escaping the nucleus. The cloud mass outflow rate is estimated to be 0.8M⊙yr−1, while the star formation rate is ∽19M⊙yr−1. Associated ionised gas, possibly generated from dissipated clouds, provides free-free absorption along the source axis, explaining the observed East-West asymmetries. We show that the clumpiness of a maser medium can have a dramatic effect on what is observed even in a relatively low gain OH megamaser. Specifically, in IIIZw35 our clumpy maser model naturally explains the large line to continuum ratios, the large 1667MHz:1665MHz line ratios and the wide velocity dispersions seen in the compact maser spots. Other astrophysical masers showing both compact and apparently diffuse emission might be explained by similar clumpy structures.
Molecular properties of (U)LIRGs: CO, HCN, HNC and HCO+
Authors: Loenen A. F. , Baan W. A. , Spaans M. 
Published: January 2008

AbstractThe observed molecular properties of a sample of FIR-luminous and OH megamaser (OH-MM) galaxies have been investigated. The ratio of high and low-density tracer lines is found to be determined by the progression of the star formation in the system. The HCO+/HCN and HCO+/HNC line ratios are good proxies for the density of the gas, and PDR and XDR sources can be distinguished using the HNC/HCN line ratio. The properties of the OH-MM sources in the sample can be explained by PDR chemistry in gas with densities higher than 105.5cm−3, confirming the classical OH-MM model of IR pumped amplification with (variable) low gains.
Zeeman splitting in OH megamasers
Authors: Robishaw Timothy , Heiles Carl , Quataert Eliot 
Published: January 2008

AbstractWe detected significant Zeeman splitting in the 1667 MHz OH megamaser emission from four ultraluminous galaxies. These detections, in addition to being the first extragalactic detection of the Zeeman effect in an emission line, suggest that OH megamasers are excellent extragalactic magnetometers.
Submillimeter and millimeter masers
Authors: Humphreys E. M. L. 
Published: January 2008

AbstractDespite theoretical predictions of the existence of many submillimeter masers, and some pioneering observational discoveries over the past few decades, these lines have remained relatively unstudied due to (i) challenges associated with observing at shorter wavelength; and, (ii) the lack of possibility of high (< 14″ at 345 GHz) angular resolution observations. With the advent of the SMA, the first submillimeter imaging array capable of sub-arcsecond resolution, APEX, and the promise of ALMA, opportunities are opening for performing new science with millimeter/submillmeter masers. In this talk, I will review recent work in the field - including extragalactic H2O millimeter masers, hydrogen recombination masers, submillimeter masers in star-forming regions, and in the envelopes of evolved stars - and discuss prospects for the future.
Submillimeter Array observations of 321 GHz water maser emission in Cepheus A
Authors: Patel Nimesh A. , Curiel Salvador , Zhang Qizhou , Sridharan T. K. , Ho Paul T. P. , Torrelles José M. 
Published: January 2008

AbstractUsing the Submillimeter Array (SMA) we have imaged for the first time the 321.226 GHz, 1029 − 936 ortho-H2O maser emission. This is also the first detection of this line in the Cepheus A high-mass star-forming region. The 22.235 GHz, 616 – 523 water masers were also observed with the Very Large Array 43 days following the SMA observations. Three of the nine detected submillimeter maser spots are associated with the centimeter masers spatially as well as kinematically, while there are 36 22 GHz maser spots without corresponding submillimeter masers. In the HW2 source, both the 321 GHz and 22 GHz masers occur within the region of ~1″ which includes the disk-jet system, but the position angles of the roughly linear structures traced by the masers indicate that the 321 GHz masers are along the jet while the 22 GHz masers are perpendicular to it. We interpret the submillimeter masers in Cepheus A to be tracing significantly hotter regions (600~2000 K) than the centimeter masers.
SMA imaging of the masers in MWC349A
Authors: Weintroub Jonathan , Moran James , Rao Ramprasad , Shinnaga Hiroko , Wilner David , Young Ken 
Published: January 2008

AbstractIn September 2004 and September 2005 we used the Submillimeter Array (SMA) to map the distribution of hydrogen recombination line (HRL) maser spots that originate in the envelope of the peculiar star MWC349A. We measured positions in the line over a 100 km/s velocity range with 1 km/s spectral resolution. Relative angular position was estimated to an accuracy of about 0.01 arcseconds. The H30α maser components can be tracked continuously in frequency between the red- and blue-shifted peaks of the spectrum. The masers appear to trace a nearly edge-on disk-like structure. The position-velocity relationship is quite remarkable, and reminiscent of that of NCG4258. However, the “wings” in the PV relation are too steep for a simple Keplerian prescription to be correct. We present our data, and suggest a simple model to account for the steep wings.
Opportunities for maser studies with the Square Kilometre Array
Authors: Green Anne J. , Baan Willem A. 
Published: January 2008

AbstractThe Square Kilometre Array (SKA) is the radio telescope of the next generation, providing an increase in sensitivity and angular resolution of two orders of magnitude over existing telescopes. Currently, the SKA is expected to span the frequency range 0.1-25 GHz with capabilities including a wide field-of-view and measurement of polarised emission. Such a telescope has enormous potential for testing fundamental physical laws and producing transformational discoveries. Important science goals include using H2O megamasers to make precise estimates of H0, which will anchor the extragalactic distance scale, and to probe the central structures of accretion disks around supermassive black holes in AGNs, to study OH megamasers associated with extreme starburst activity in distant galaxies and to study with unprecedented precision molecular gas and star formation in our Galaxy.
Glucose Tolerance, Lipids, and GLP‐1 Secretion in JCR:LA‐cp Rats Fed a High Protein Fiber Diet
Authors: Reimer Raylene A. , Russell James C. 
Published: January 2008

Background: We have shown that individually, dietary fiber and protein increase secretion of the anorexigenic and insulinotropic hormone, glucagon‐like peptide‐1 (GLP‐1).Objective: Our objective was to combine, in one diet, high levels of fiber and protein to maximize GLP‐1 secretion, improve glucose tolerance, and reduce weight gain.Methods and Procedures: Lean (+/?) and obese (cp/cp) male James C Russell corpulent (JCR:LA‐cp) rats lacking a functional leptin receptor were fed one of four experimental diets (control, high protein (HP), high fiber (HF, prebiotic fiber inulin), or combination (CB)) for 3 weeks. An oral glucose tolerance test (OGTT) was performed to evaluate plasma GLP‐1, insulin and glucose. Plasma lipids and intestinal proglucagon mRNA expression were determined.Results: Energy intake was lower with the HF diet in lean and obese rats. Weight gain did not differ between diets. Higher colonic proglucagon mRNA in lean rats fed a CB diet was associated with higher GLP‐1 secretion during OGTT. The HP diet significantly reduced plasma glucose area under the curve (AUC) during OGTT in obese rats, which reflected both an increased GLP‐1 AUC and higher fasting insulin. Diets containing inulin resulted in the lowest plasma triglyceride and total cholesterol levels.Discussion: Overall, combining HP with HF in the diet increased GLP‐1 secretion in response to oral glucose, but did not improve glucose tolerance or lipid profiles more than the HF diet alone did. We also suggest that glycemic and insulinemic response to prebiotics differ among rat models and future research work should examine their role in improving glucose tolerance in diet‐induced vs. genetic obesity with overt hyperleptinemia.
Insurance Coverage and Incentives for Weight Loss Among Adults With Metabolic Syndrome
Authors: Arterburn David , Westbrook Emily O. , Wiese Cheryl J. , Ludman Evette J. , Grossman David C. , Fishman Paul A. , Finkelstein Eric A. , Jeffery Robert W. , Drewnowski Adam 
Published: January 2008

Objective: To describe how insured adults with metabolic syndrome respond to various options for insurance coverage and financial incentives for weight management.Methods and Procedures: Insured adults meeting the criteria for the metabolic syndrome were randomly identified through automated medical records and invited to participate in a telephone‐based survey of the acceptability of various weight management programs—with different financial incentives and insurance coverage options—in a health maintenance organization. Multivariable logistic regression models were used to test the relationship between participant characteristics and the odds of being motivated by incentives.Results: One hundred and fifty‐three adults with the metabolic syndrome completed the survey (i.e., 79% of telephone contacts). A hypothetical increase in insurance coverage from 10 to 100% led to a threefold increase among women and a sevenfold increase among men in the proportion reporting they were “very interested” in enrolling in a weight management program within the next 30 days. Most participants (76% of women and 57% of men) supported a health plan–sponsored financial incentive program tied to weight loss, and 41% believed such a program would motivate them to lose weight. The mean financial incentive proposed for a 15‐pound weight loss was $591 (median: $125).Discussion: Although weight loss is an effective treatment for metabolic syndrome, standard health insurance rarely covers intensive behavioral treatment. The results of this study suggest that providing full insurance coverage and financial incentives for weight management increases the interest in participating in obesity treatment programs. Further research should determine how full coverage and incentives affect participation rates, long‐term body weight changes, and costs.
Attenuation of Vascular/Neural Dysfunction in Zucker Rats Treated With Enalapril or Rosuvastatin
Authors: Oltman Christine L. , Davidson Eric P. , Coppey Lawrence J. , Kleinschmidt Travis L. , Lund Donald D. , Yorek Mark A. 
Published: January 2008

Objective: Obese Zucker rats, animal model for the metabolic syndrome, develop a diabetes‐like neuropathy that is independent of hyperglycemia. The purpose of this study was to determine whether drugs used to treat cardiovascular dysfunction in metabolic syndrome also protect nerve function.Methods and Procedures: Obese Zucker rats at 20 weeks of age were treated for 12 weeks with enalapril or rosuvastatin. Lean rats were used as controls. Vasodilation in epineurial arterioles was measured by videomicroscopy. Endoneurial blood flow (EBF) was measured by hydrogen clearance and nerve conduction velocity was measured following electrical stimulation of motor or sensory nerves.Results: Enalapril treatment decreased serum angiotensin‐converting enzyme (ACE) activity and both drugs reduced serum cholesterol levels. In obese Zucker rats at 32 weeks of age superoxide levels were elevated in the aortas and epineurial arterioles, which were reduced by treatment with either drug. Nitrotyrosine levels were increased in epineurial arterioles and reduced with enalapril treatment. EBF was decreased and corrected by treatment with either drug. Motor nerve conduction velocity was decreased and significantly improved with enalapril treatment. Obese Zucker rats were hypoalgesic in response to a thermal stimulus and this was significantly improved with either treatment. Treatment with either enalapril or rosuvastatin significantly reversed the decrease in acetylcholine‐mediated vascular relaxation of epineurial arterioles in obese Zucker rats.Discussion: Even though obese Zucker rats have normal glycemia vascular and neural dysfunctions develop with age and can be improved by treatment with either enalapril or rosuvastatin.
Vitamin D Status and Response to Vitamin D3 in Obese vs. Non‐obese African American Children
Authors: Rajakumar Kumaravel , Fernstrom John D. , Holick Michael F. , Janosky Janine E. , Greenspan Susan L. 
Published: January 2008

Background: Serum 25‐hydroxyvitamin D (25(OH)D) is low in obese adults.Objective: To examine serum 25(OH)D in obese (BMI >95th percentile for age) vs. non‐obese (BMI = 5th–75th percentile for age) 6–10‐year‐old African American children and compare their differences in therapeutic response to vitamin D supplementation.Methods and Procedures: In an open label non‐randomized pre‐post comparison 21 obese (OB) and 20 non‐obese (non‐OB) subjects matched for age, sex, skin color, and pubertal maturation were treated with 400 IU of vitamin D3 daily for 1 month. Serum 25(OH)D, 1,25‐dihydroxyvitamin D (1,25(OH)2D), parathyroid hormone (PTH), leptin, and markers of bone turnover (serum bone‐specific alkaline phosphatase (BSAP), osteocalcin (OC), and urine n ‐telopeptide cross‐links of type 1 collagen (urine NTX)) were measured. Vitamin D deficiency was defined as serum 25(OH)D ≤20 ng/ml and insufficiency as 21–29 ng/ml respectively.Results: Vitamin D deficiency occurred in 12/21 (57%) OB vs. 8/20 (40%) non‐OB at baseline (P = 0.35) and persisted in 5/21 (24%) OB vs. 2/18 (11%) non‐OB (P = 0.42) after treatment. When the cohort was stratified by the baseline levels of 25(OH)D, there were differences in the response to treatment in the obese and non‐obese cohorts.Discussion: Vitamin D deficiency was common among OB and non‐OB preadolescent African American children, and 400 IU of vitamin D3 (2× the recommended adequate intake) daily for 1 month was inadequate to raise their blood levels of 25(OH)D to ≥30 ng/ml.
Guggulsterone Inhibits Adipocyte Differentiation and Induces Apoptosis in 3T3‐L1 Cells
Authors: Yang Jeong‐Yeh , Della‐Fera Mary Anne , Baile Clifton A. 
Published: January 2008

Objective: To determine the effects of guggulsterone (GS), the active substance in guggulipid, on apoptosis, adipogenesis, and lipolysis using 3T3‐L1 cells.Methods and Procedures: For apoptosis and lipolysis experiments, mature adipocytes were treated with GS isomers. Viability, apoptosis, and caspase 3/7 activation were quantified using MTS, enzyme‐linked immunosorbent assay (ELISA), caspase‐Glo 3/7 activity assay, respectively. The expression of cytochrome c was demonstrated by western blot. Lipolysis was quantified by measuring the release of glycerol. For adipogenesis experiments, postconfluent preadipocytes were incubated with GS isomers for up to 6 days during maturation. Adipogenesis was quantified by measuring lipid content using Nile Red dye. Western blot was also used to demonstrate the adipocyte‐specific transcription factors peroxisome proliferator–activated receptor γ2 (PPARγ2), CCAAT/enhancer binding protein α (C/EBPα), and C/EBPβ.Results: In mature adipocytes cis‐GS decreased viability, whereas the trans‐GS isomer had little effect. Both isomers caused dose‐dependent increases in apoptosis and cis‐GS was more effective than trans‐GS in inducing apoptosis. cis‐ and trans‐GS also increased caspase‐3 activity and release of cytochrome c from mitochondria. In maturing preadipocytes, both isomers were equally effective in reducing lipid content. The adipocyte‐specific transcription factors PPARγ2, C/EBPα, and C/EBPβ were downregulated after treatment with cis‐GS during the maturation period. Furthermore, cis‐GS increased basal lipolysis of mature adipocytes, but trans‐GS had no effect.Discussion: These results indicate that GS isomers may exert antiobesity effects by inhibiting differentiation of preadipocytes, and by inducing apoptosis and promoting lipolysis of mature adipocytes. The cis‐GS isomer was more potent than the trans‐GS isomer in inducing apoptosis and lipolysis in mature adipocytes.
Adiponectin and Metabolic Syndrome in Middle‐aged and Elderly Chinese
Authors: Wang Jing , Li Huaixing , Franco Oscar H. , Yu Zhijie , Liu Yong , Lin Xu 
Published: January 2008

Objective: Hypoadiponectinemia is an important risk factor for metabolic syndrome (MetS). However, little is known about its role in the Chinese population. The aim of this study was to investigate the association between plasma adiponectin levels and MetS in middle‐aged and elderly Chinese from both urban and rural areas of northern and southern China.Methods and Procedures: This population‐based cross‐sectional study included 3,193 subjects aged 50–70 from urban and rural areas of Beijing (northern China) and Shanghai (southern China). Plasma adiponectin concentrations were measured using a high‐throughput micro‐assay, Luminex. MetS was identified with the updated National Cholesterol Education Program Adult Treatment Panel III (NCEP ATP III) criteria.Results: Adiponectin levels were significantly higher in female, and rural subjects than in male or urban residents (P < 0.001). The prevalence and the number of MetS components progressively increased with declined adiponectin levels (P for trend <0.001). The participants in the lowest adiponectin quartile had a significantly increased risk for acquiring MetS (odds ratio (OR) 3.38, 95% confidence interval (CI) 2.56–4.46) after adjustment for potential confounders. Subjects from Beijing or rural areas had a higher risk for MetS at the same given level of adiponectin than did their Shanghai or urban counterparts, respectively.Discussion: Adiponectin is negatively associated with MetS in the middle‐aged and elderly Chinese independent of known confounders such as BMI, physical activity and life habits. The urban–rural and northern–southern differences in susceptibility to MetS should be taken into consideration for the early detection and prevention of MetS.
Prevalence and Associated Factors of Overweight and Obesity in a Chinese Rural Population
Authors: Zhang Xingang , Sun Zhaoqing , Zhang Xinzhong , Zheng Liqiang , Liu Shuangshuang , Xu Changlu , Li Jiajin , Zhao Fenfen , Li Jue , Hu Dayi , Sun Yingxian 
Published: January 2008

Background: Overweight and obesity are now considered as a serious health problem, and a very important risk factor for many diseases.Objective: This study was designed to investigate the epidemiologic features of overweight and obesity among rural adults in China.Method and Procedures: A cross‐sectional survey was conducted during 2004–2005, using a multistage cluster sampling method to select a representative sample in Fuxin county, Liaoning province, China. A total of 29,970 adults, aged ≥35 years, were examined. At baseline, lifestyle and other factors were obtained. Overweight and obesity were defined according to the classification by the World Health Organization.Results: Overall, the prevalence of overweight was 18.6%; 15.1% in men and 22.1% in women. The prevalence of obesity was 1.7%; 1.2% in men and 2.2% in women. Multivariable logistic regression revealed certain risk factors of obesity that included being a women, Mongolian nationality and education status of over junior high school level. Moderate physical activity alone was shown as protective factor.Discussion: Although the prevalence of obesity was low, overweight was relatively high in the Chinese rural population, especially in adult women. Gender, diet, physical activity, education levels, and ethnicity were associated with the prevalence of these health conditions.
Physical Activity Patterns in the National Weight Control Registry
Authors: Catenacci Victoria A. , Ogden Lorraine G. , Stuht Jennifer , Phelan Suzanne , Wing Rena R. , Hill James O. , Wyatt Holly R. 
Published: January 2008

Objective: The National Weight Control Registry (NWCR) was established in 1993 to examine the characteristics of those who are successful at weight loss: individuals maintaining a 13.6‐kg weight loss for >1 year. The size of the registry has increased substantially since the early descriptions of this group a decade ago. The purpose of this study was to describe in detail the weekly physical activity habits of NWCR members, to examine the relationship between amount of activity and demographic characteristics, and to determine if changes in activity parameters have occurred over time.Methods and Procedures: Participants were 887 men and 2,796 women who enrolled in the NWCR between 1993 and 2004. Physical activity was evaluated at registry entry using the Paffenbarger Physical Activity Questionnaire.Results: NWCR entrants report an average of 2,621 ± 2,252 kcal/week in physical activity. There is considerable variability in the amount of activity reported: 25.3% report <1,000 kcal/week and 34.9% report >3,000 kcal/week. Activity level on registry entry is related to the magnitude but not the duration of weight loss. The amount of activity reported by men has decreased over time while no significant change was observed in women. Changes in the types of activities most frequently reported were also observed.Discussion: Overall, NWCR participants are an extremely physically active group. However, the amount of activity reported is highly variable, making it difficult to develop a single recommendation for the optimum amount of physical activity for weight loss maintenance. A better understanding of individual‐specific determinants of how much activity is required for weight loss maintenance ought to be a high research priority.