Search Results - (Author, Cooperation:J. Urban)

2018-01-05

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Geosciences

Computer Science

Medicine

Natural Sciences in General

Physics

Microbiology

2018-06-22

Nature Publishing Group (NPG)

2045-2322

Natural Sciences in General

2018-09-18

The American Association of Immunologists (AAI)

0022-1767

1550-6606

Medicine

2018-04-26

American Association for the Advancement of Science (AAAS)

2375-2548

Natural Sciences in General

2012-04-14

American Association for the Advancement of Science (AAAS)

0036-8075

1095-9203

Biology

Chemistry and Pharmacology

Computer Science

Medicine

Natural Sciences in General

Physics

Access to Information ; Disclosure ; Editorial Policies ; *Information Dissemination ; Public Policy ; *Publishing ; *Research ; Research Support as Topic ; *Software

2018-12-17

Italian Society of Silviculture and Forest Ecology

1971-7458

Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

1432-0827

Calcitonin ; Calcitriol ; Calcium ; Densitometry ; Osteoporosis

Springer Online Journal Archives 1860-2000

Biology

Medicine

Physics

Summary Twenty-two middle-aged women with severe osteoporosis were treated for 2 years with either 0.5 mg of synthetic human calcitonin subcutaneously three times per week combined with 0.5 μg of calcitriol and 0.5 g of calcium per day orally or calcium only. The treatment with calcitonin plus calcitriol (12 patients) resulted in a significantly increased calcium absorption rate. The mean values for serum phosphate did not change during the treatment period and the mean values did not differ between the treatment groups, but the serum calcium and urinary Ca/Cr ratio increased somewhat in the group given the combined treatment. There was no evidence that the combined treatment improved the bone density in this study. It is possible that calcitriol, instead of increasing the effect of calcitonin by suppression of the parathyroid, might have counteracted its effect by increasing the bone resorption.

Electronic Resource

1432-0827

45Calcium ; Immobilization ; Osteoporosis ; Parathyroid glands ; Thyroparathyroidectomy

Springer Online Journal Archives 1860-2000

Biology

Medicine

Physics

Abstract In order to study the role played by the thyroid and the parathyroid glands in the development of osteoporosis induced by immobilization, 153 male adult Sprague-Dawley rats allocated in two groups were used. The animals of one group were thyroparathyroidectomized; those of the other group were left intact. Each group was then divided into two subgroups; in one the right hind leg of the animals were immobilized by an elastic adhesive bandage. The animals were observed for varying periods of time up to 16 weeks. Studies of bone mass and45Ca accretion rate of the right and left femur and tibia were performed in all animals. The results indicate that disuse osteoporosis occurs in rats in the virtual absence of the thyroid and parathyroid glands. The bone loss of the immobilized femur and tibia was less pronounced in thyroparathyroidectomized rats compared to intact rats. The uptake of45Ca in bone treated by immobilization as compared to the non-immobilized bone was found to be increased to the same proportion in thyroparathyroidectomized and in intact rats. The calcium-accretion rate of non-immobilized bone was lower in thyroparathyroidectomized than in intact rats. The observations indicate that in the rat the parathyroid and thyroid hormones influence the rate of bone turnover and thereby the rate of development of disuse osteoporosis.

Electronic Resource

1573-7217

tamoxifen ; keoxifene ; osteoporosis ; bone density ; antiestrogens

Springer Online Journal Archives 1860-2000

Medicine

Summary The effects of the antiestrogens tamoxifen and keoxifene on the bone density of intact and ovariectomized female rats were determined after 4 months of therapy. The antiestrogens did not cause a decrease in bone density in intact animals, although uterine wet weight did decrease. Ovariectomy caused an increase in body weight (25%) and a significant decrease in femur density (P〈0.01). Antiestrogens did not further decrease the bone density of ovariectomized rats but rather helped to maintain bone density. Antiestrogens as well as estrogen (oral estradiol benzoate 25µg daily) helped to maintain bone density in the range observed for the intact rats, but inhibited estrogen stimulation of uterine weight. These contrasting pharmacological actions of antiestrogens suggest that patients receiving long-term adjuvant tamoxifen therapy for breast cancer should be evaluated to determine whether tamoxifen can retard the development of osteoporosis.

Electronic Resource

2018-09-01

American Physical Society (APS)

0556-2813

1089-490X

Physics

Nuclear Structure

2018-11-06

The American Association of Immunologists (AAI)

0022-1767

1550-6606

Medicine

2018-10-23

The American Association of Immunologists (AAI)

0022-1767

1550-6606

Medicine

2018-12-17

Italian Society of Silviculture and Forest Ecology

1971-7458

Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

2018-12-17

Italian Society of Silviculture and Forest Ecology

1971-7458

Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

1077-3118

AIP Digital Archive

Physics

The structures of small silver clusters supported by carbon have been determined in high-resolution electron microscopy. Undistorted crystals displaying fivefold and threefold symmetries were found with sizes ranging from 30 to 100 A(ring). Such large particles displaying fivefold symmetries are generally believed to be unstable. However, in this case stabilization was achieved by shifting the center of symmetry with respect to the individual faces. The magnitude of the shift increases with the growth of the particles. The center of symmetry for particles with a threefold axis was always found to be unshifted.

Electronic Resource

1471-0528

Blackwell Publishing Journal Backfiles 1879-2005

Medicine

Summary. The influence of dopamine on uterine activity was studied by external tocography in women at the end of a normal pregnancy. In those who were not in labour dopamine infusion (4 μg min-1 kg-1 body weight) induced regular uterine contractions and with higher doses the response increased. For women in spontaneous labour, dopamine at a dose of 4 SmUg min-1 kg-1 caused a significant increase in the frequency of contraction, but in women receiving an oxytocin infusion, no further stimulation was seen. Dopamine did not have any noticeable effect on fetal heart rate, maternal pulse rate or blood pressure and no other general effects were observed.

Electronic Resource

1745-6584

Blackwell Publishing Journal Backfiles 1879-2005

Energy, Environment Protection, Nuclear Power Engineering

Geosciences

The bedrock profile of an east–central Pennsylvania watershed contains a shallow weathered fracture layer. To begin quantifying the effects of this fracture layer on ground–water movement, two valley cross sections were chosen for detailed investigation. One section represents the typical upland watershed situation where the regional ground water is in contact with the stream for only part of the year, while at the other section the regional ground water is in perennial contact with the stream. Rock cores extracted from the sections reveal a pattern of extensive fracturing to approximately 50 ft directly under the stream thinning to a relatively uniform 30–ft deep fracture layer away from the channel. Limited seismic investigations support these observations. Piezometers within each cross section show that hydraulic conductivity differs between the shallow fracture layer and the relatively unfractured zone below and that there is great variability in conductivity within the fracture layer itself. Lateral flow generally occurs within the fracture layer to within approximately 50 ft of the stream; here a converging flow pattern indicates ground–water discharge to the stream. Under wet conditions, the stream in each section serves as a point of ground-water discharge, while under dry conditions, the more upland section shows no ground–water discharge to the land surface. Rather, subsurface flow is likely occurring beneath and parallel to the channel controlled by a discharge point at some downstream location. Finally, water–quality samples from the piezometers indicate a direct effect of overlying land use on water quality within the shallow fracture layer.

Electronic Resource

1745-6584

Blackwell Publishing Journal Backfiles 1879-2005

Energy, Environment Protection, Nuclear Power Engineering

Geosciences

Porous asphalt pavement is a storm-water management technique which reduces runoff and enhances ground-water recharge. Planned applications of this, or other ground-water recharge techniques, require that ground-water response to induced recharge be quantified. Here, we emphasize determination of the aquifer parameters hydraulic conductivity (K) and specific yield (Sy) at a porous asphalt ground-water recharge facility installed near Willow Grove, Pennsylvania.We compare values of these aquifer properties derived from conventional laboratory and field techniques to those derived using recharge event data collected at the site. By the comparisons, we illustrate the techniques of aquifer property determination apropos to the design of ground-water recharge installations. Because of the fractured nature of the aquifer, the K-values determined from pumping test and slug test analyses are about an order of magnitude greater than those of rock core samples, while the field-based specific yield values are about an order of magnitude less than effective porosities of the rock cores. Ratios of K/Sy derived from a chemical tracer test agree with the pumping test values. Finally, the K and Sy necessary to simulate facility response to recharge using a numerical model of ground-water flow correspond to those derived from field-oriented techniques rather than those of the rock cores.The results show that the design parameters K and Sy should be obtained from field-based techniques, such as the nonsteady pump test, which match the time and space scale in which the facility is expected to affect the aquifer.

Electronic Resource

1089-7690

AIP Digital Archive

Physics

Chemistry and Pharmacology

Electron impact ionization cross sections measured close to threshold are reported for both the monomers and dimers of ozone and OClO using a new high resolution electron impact apparatus. The present appearance energies AE(O3+/O3)=12.70±0.02 eV, AE (OClO+/OClO)=10.55±0.02 and AE(ClO+/OClO=13.37±0.03 eV derived from the measured ionization cross sections are in excellent agreement with the vertical threshold values determined for these ions by high resolution PES and PIMS photoionization studies. The corresponding appearance energies determined for the dimer ions, 10.10±0.3 eV for (O3)2+ and 9.87±0.2 eV for (OClO)2+, are both red shifted with respect to the monomer case. The bond energy (0.70–0.3+0.5) eV of (OClO)2+ estimated from these data is similar to that of other dimer ions, whereas the bond energy of (O3–O3+) with (2.55−0.4+0.6) eV is rather large suggesting an unusual structure for the cationic ozone dimer ion. Based on quantum chemical calculations on various levels we are led to the conclusion that the ion produced by ionization of the ozone dimer is no longer a conventional dimer ion where the two monomer units are still present (as is the case for the OClO system), but rather an ion of form O2(centered ellipsis)O4+ or a twisted ring structure of (O6)+. © 2002 American Institute of Physics.

Electronic Resource

1745-6592

Blackwell Publishing Journal Backfiles 1879-2005

Energy, Environment Protection, Nuclear Power Engineering

Geosciences

Pumped waters from 14 Pennsylvania wells, located in shallow sandstone, siltstone and shale aquifers, were continuously monitored for dissolved oxygen (D. O.), nitrate (NO3), pH, electrical conductivity (EC) and water temperature in a discharge manifold at the well head. The amount of pumping or purging required to stabilize these parameter readings varied by well site and parameter being analyzed. However, the purging required was generally greatest for D. O. and least for water temperature where: D. O. 〈 NO3 pH 〈 EC 〈 water temperature. Wells located near the siltstone-shale interface generally required far more purging than did wells located elsewhere. Although parameter stability was often achieved within purging one bore volume, the complexity, diversity, and variability in the data and these well-ground water systems, suggest that no single purging rule is appropriate. Instead, the extent of purging required before sampling these shallow aquifers should be determined by incorporating on-site monitoring of target or related parameters into the purging process.From a sampling perspective, the relationship between NO3 and D. O. concentrations during purging were analyzed relative to aquifer type. For most wells located in sandstone or siltstone, NO3 concentrations remained relatively constant during purging irrespective of changes in D. O. For most wells located in shale, these two were positively and similarly correlated, suggesting that a general relationship exists.

Electronic Resource