bluuebunny/crossref_metadata_2025 huggingface dataset:
Efficacy and safety of pimecrolimus cream 1% in adult patients with vitiligo: Results of a randomized, double‐blind, vehicle‐controlled study
Authors: Dawid Markus , Veensalu Marge , Grassberger Maximilian , Wolff Klaus
Published: October 2006

Background: Vitiligo is an acquired, pigmentary skin disorder which is disfiguring and difficult to treat. In an earlier open label study in adult patients with vitiligo, pimecrolimus cream 1% was reported to have similar efficacy as clobetasol propionate 0.05%. We performed a double‐blind, intrapatient comparison of pimecrolimus cream 1% with placebo cream.

Patients and methods: Twenty adult Caucasians with symmetrical vitiligo (predominantly on extremities, none in the face) were treated b.i.d. for 6 months left/right with pimecrolimus/vehicle (N = 10) or vehicle/pimecrolimus (N = 10), respectively. Primary efficacy endpoint was the size of the target lesion at month 6 and secondary efficacy endpoint was re‐pigmentation.

Results: Treatment with pimecrolimus cream 1% or vehicle resulted in no significant change in mean target lesion size. Modest repigmentation (1–25%) was noted with pimecrolimus at month 2 in 12 of 17 patients (vehicle: 9 of 17 patients). Afterwards, the number of patients who experienced an improvement of pigmentation steadily decreased (3 of 14 patients with pimecrolimus and 2 of 14 with placebo at month 6).Treatment was well tolerated.There were no treatment‐related adverse events, no induction of skin atrophy nor any other application site side effects.

Conclusion: In this group of adult patients with symmetrical vitiligo, treatment of body lesions (except face) with pimecrolimus cream 1% could not be shown to be effective.
Successful thalidomide therapy for actinic prurigo in a European woman
Authors: Holzer Anna , Wolf Peter , Legat Franz J. , Kerl Helmut , Hofer Angelika
Published: October 2006

Actinic prurigo is a rare, often difficult‐to‐treat, idiopathic photodermatosis. Actinic prurigo is divided into a hereditary form appearing in the Native American population and a sporadic form occurring in non‐Native Americans. We present a 28‐year‐old Caucasian woman who developed typical clinical signs and symptoms of actinic prurigo, just as had her mother and grandmother. The patient and her mother were HLA‐A24 and HLA‐DR 4 with the subtype HLA‐DRB1*0408. Based on clinical symptoms and the HLA pattern, the diagnosis of actinic prurigo was made. Treatment with thalidomide led to resolution of the disease. This case report of a Caucasian woman suffering from a hereditary form of actinic prurigo questions the established classification of actinic prurigo into a hereditary Native American form and a sporadic form occurring in the non‐Native American population.
Gas6 and protein S
Authors: Hafizi Sassan , Dahlbäck Björn
Published: October 2006

Gas6 and protein S are two homologous secreted proteins that depend on vitamin K for their execution of a range of biological functions. A discrete subset of these functions is mediated through their binding to and activation of the receptor tyrosine kinases Axl, Sky and Mer. Furthermore, a hallmark of the Gas6–Axl system is the unique ability of Gas6 and protein S to tether their non receptor‐binding regions to the negatively charged membranes of apoptotic cells. Numerous studies have shown the Gas6–Axl system to regulate cell survival, proliferation, migration, adhesion and phagocytosis. Consequently, altered activity/expression of its components has been detected in a variety of pathologies such as cancer and vascular, autoimmune and kidney disorders. Moreover, Axl overactivation can equally occur without ligand binding, which has implications for tumorigenesis. Further knowledge of this exquisite ligand–receptor system and the circumstances of its activation should provide the basis for development of novel therapies for the above diseases.
Cascading extinctions and ecosystem functioning: contrasting effects of diversity depending on food web structure
Authors: Thébault Elisa , Huber Veronika , Loreau Michel
Published: October 2006

The consequences of species loss on cascading extinctions in food webs have been the focus of several recent theoretical studies, with differing results. Changes in ecosystem properties consecutive to cascading extinctions have received far less attention even though such dramatic events might strongly alter ecosystem functioning. Here we use various food web models to investigate the effects of species loss and diversity on both secondary extinctions and their associated changes in ecosystem properties. Our analysis shows that diversity has contrasting effects depending on the presence of self‐limiting terms at consumer levels and, to a lower extent, on connectance and interspecific competition. Ecosystems that lose a high proportion of species through cascading extinctions exhibit the most important changes in ecosystem properties. Linking studies on cascading extinctions in food webs with studies that investigate the effects of biodiversity on ecosystem functioning appears crucial for a better understanding of the consequences of species extinctions.
Only noise can induce chaos in discrete populations
Authors: Scheuring István , Domokos Gábor
Published: October 2006

Motivated by the papers from Ellner and Turchin 2005 and Dennis et al. 2003 we investigate the possibility to detect chaos in noisy ecological systems. One message of our paper is that if a dynamic model is available and if this model predicts chaotic behaviour, one should consider its discrete‐state, noisy version when fitting numerical predictions to observations. We emphasize that deterministic discrete‐state models behave periodically, thus only the interaction of these deterministic skeletons with random noise can produce non‐regular dynamics. We detect and describe a relatively sharply defined range of the noise (the grey zone) where the gradual transition from periodic to chaotic behaviour happens. This zone, the upper border of which can be predicted analytically, is identified in experimental data as well as in numerical simulations. In the grey zone the global, statistical behaviour will approach the statistics produced by the chaotic, continuous model, and in this sense we claim that noise can produce chaos.
The observed range for temporal mean‐variance scaling exponents can be explained by reproductive correlation
Authors: Ballantyne IV Ford , J. Kerkhoff Andrew
Published: October 2006

The mean‐variance scaling relationship known as Taylor's power law has been well documented empirically over the past four decades but a general theoretical explanation for the phenomenon does not exist. Here we provide an explanation that relates empirical patterns of temporal mean‐variance scaling to individual level reproductive behavior. Initially, we review the scaling behavior of population growth models to establish theoretical limits for the scaling exponent b that is in agreement with the empirically observed range (1≤b≤2). We go on to show that the degree of reproductive covariance among individuals determines the scaling exponent b. Independent reproduction results in an exponent of one, while completely correlated reproduction results in the upper limit of two. Intermediate exponents, which are common empirically, can be generated through the decay of reproductive covariance with increasing population size. Finally, we describe how the link between reproductive correlation and the scaling exponent provides a way to infer properties of individual‐level reproductive behavior, such as the relative influence of demographic stochasticity, from a macroecological pattern.
Stick-Slip and Bit-Bounce Interaction in Oil-Well Drillstrings
Authors: Yigit Ahmet S. , Christoforou Andreas P.
Published: October 2006

Drillstring vibrations and in particular stick-slip and bit-bounce are detrimental to oil-well drilling operations. Controlling these vibrations is essential because they may cause equipment failures and damage to the oil-well. A simple model that adequately captures the dynamics is used to simulate the effects of varying operating conditions on stick-slip and bit-bounce interactions. It is shown that the conditions at the bit/formation interface, such as bit speed and formation stiffness, are major factors in shaping the dynamic response. Due to the varying and uncertain nature of these conditions, simple operational guidelines or active rotary table control strategies are not sufficient to eliminate both stick-slip and bit-bounce. It is demonstrated that an additional active controller for the axial motion can be effective in suppressing both stick-slip and bit-bounce. It is anticipated that if the proposed approach is implemented, smooth drilling will be possible for a wide range of conditions.
Optimal Design of Progressing Cavity Pumps(PCP)
Authors: Robello Samuel G. , Saveth Ken J.
Published: October 2006

The drive for energy independence has created a window of opportunity for innovations in oil recovery. New artificial lift methods like progressing cavity pumping have been successfully applied to downhole pumping applications. The multilobe pumps are also making inroads into the industry to be used under different operating conditions. Although the design has been mainly based on empirical standards and trial and error modifications, a more phenomenally optimum design of the pump is required to achieve a high efficiency standard. The optimal relationship between the pitch and the diameter of the housing is obtained to achieve a maximum flow rate for multilobe pumps.
Optimal Allocation of Lift-Gas Rates Under Multiple Facility Constraints: A Mixed Integer Linear Programming Approach
Authors: Camponogara Eduardo , Nakashima Paulo H. R.
Published: October 2006

The effective application of continuous gas lift entails solving the combinatorial optimization problem of optimally allocating limited resources. This work proposes a mixed integer linear formulation for the problem of maximizing oil field profit under multiple facility constraints such as limited lift gas, fluid handling, and storage capacities. Families of valid inequalities are identified and introduced into the basic model to render a stronger formulation. Numerical experiments using commercial and non-commercial software, and comparisons with published results, show that the proposed method yields fast solution with significant average increase in oil production rate and profit.
Feasible Experimental Study on the Utilization of a 300MW CFB Boiler Desulfurizating Bottom Ash for Construction Applications
Authors: Lu Xiaofeng , Amano R. S.
Published: October 2006

Circulating fluidized bed (CFB) boiler has entered electric power industry field because of burning a wide range of fuels, while still achieving strict air emissions requirements. This study focuses on a 300MW CFB boiler, which will be one of the largest CFB boiler in the world. In a CFB boiler, fuels were burned with the addition of limestone to capture SO2 in a solid form. Therefore, the volume of ashes, both bottom ash and fly ash, discharged from a CFB boiler is much higher than the ashes discharged from a pulverized coal-fired (PC) boiler at the same capacity of the boiler. CFB boiler ash cannot be used as a cement replacement in concrete due to its unacceptably high sulfur content. The disposal in landfills has been the most common means of handling ash in circulating fluidized bed boiler power plants. However, for a 300MW CFB boiler power plant, there will be 600,000tons of ash discharged per year and will result in great volumes and disposal cost of ash byproduct. It was very necessary to solve the utilization of CFB ash and to decrease the disposal cost of CFB ash. The feasible experimental study results on the utilization of the bottom ashes of a 300MW CFB boiler in Baima power plant in China were reported in this paper. The bottom ashes used for test came from the discharged bottom ashes in a 100MW CFB boiler in which the anthracite and limestone designed for the 300MW CFB project was burned. The results of this study showed that the bottom ash could be used for cementitious material, road concrete, and road base material. The masonry cements, road concrete with 30MPa compressive strength and 4.0MPa flexural strength, and the road base material used for base courses of the expressway, the main road and the minor lane were all prepared with milled CFB bottom ashes in the lab. The better methods of utilization of the bottom ashes were discussed in this paper.
Interaction of
Beggiatoa
and Rice Plant: Detoxification of Hydrogen Sulfide in the Rice Rhizosphere
Authors: Joshi M. M. , Hollis J. P.
Published: October 2006

Beggiatoa
was obtained from six habitats, including four water-saturated soils from rice fields. The isolate of
Beggiatoa
from Bernard clay, when reinoculated into soil treatments from pure culture, significantly reduced hydrogen sulfide levels in soils and increased oxygen release from rice plants. Rice plants significantly increased
Beggiatoa
survival in flooded soils. Some hydrogen sulfide was necessary for survival of the Bernard clay isolate; high concentrations of hydrogen sulfide killed the Bernard clay isolate but were tolerated by a Crowley silt loam isolate from Eagle Lake, Texas. The results suggest that
Beggiatoa
may be an element of wetlands plant ecosystems.
Star Dust
Authors: Ney Edward P.
Published: October 2006

Infrared astronomy has shown that certain classes of stars are abundant producers of refractory grains, which condense in their atmospheres and are blown into interstellar space by the radiation pressure of these stars. Metallic silicates of the kind that produce terrestrial planets are injected by the oxygen-rich stars and carbon and its refractories by carbon stars. Much of the interstellar dust may be produced by this mechanism. A number of "infrared stars" are completely surrounded by their own dust, and a few of these exhibit a unique morphology that suggests the formation of a planetary system or a stage in the evolution of a planetary nebula. Certain novae also condense grains, which are blown out in their shells.

In our own solar system, comets are found to contain the same silicates that are present elsewhere in the galaxy, suggesting that these constituents were present in the primeval solar nebula.
Visual Detection of Cryptic Prey by Blue Jays (
Cyanocitta cristata
)
Authors: Pietrewicz Alexandra T. , Kamil Alan C.
Published: October 2006

Blue jays learned to respond differentially to the presence or absence of
Catocala
moths in slides. This detection of the moths by the jays was affected by the background upon which the moth was placed and its body orientation, thus providing an objective measure of crypticity. These procedures are useful for the study of visual detection of prey.
Chitinozoans from the Late Precambrian Chuar Group of the Grand Canyon, Arizona
Authors: Bloeser Bonnie , Schopf J. William , Horodyski Robert J. , Breed William J.
Published: October 2006

Carbonaceous shales of the late Precambrian Chuar Group of the Grand Canyon, Arizona, contain abundant and well-preserved chitinozoans. The occurrence of these distinctive, tear- and flask-shaped microfossils, the oldest chitinozoans now known and the first to be reported from the Precambrian, seems to suggest that heterotrophic protists (or primitive metaozoans) were extant at least as early as about 750 ± 100 million years ago.
Social Behavior in Hatchling Green Iguanas: Life at a Reptile Rookery
Authors: Burghardt Gordon M. , Greene Harry W. , Rand A. Stanley
Published: October 2006

Hatchling green iguanas (
Iguana iguana
) emerge from the ground in small groups in a communal nesting area on a small Panamanian islet and engage in complex social interactions. Iguanas from different clutches often join together before and during departure from the nest site. They also usually move around the islet and migrate from it to the larger adjacent landmass in social groups. These and other observations indicate that the sophistication of saurian social organization and neonate behavior has been underestimated.
Behavioral Control of Workers by Queens in Primitively Eusocial Bees
Authors: Breed Michael D. , Gamboa George J.
Published: October 2006

Queens of
Lasioglossum zephyrum
, a primitively eusocial bee, are considerably more active than workers. The queen's behavior stimulates worker activities; removal of the queen results in a marked reduction in activities of other bees. The queen not only activates workers but also directs them by a primitive recruitment behavior suggestive of tandem running of highly eusocial ants.
Eruptions of the St. Augustine Volcano: Airborne Measurements and Observations
Authors: Hobbs Peter V. , Radke Lawrence F. , Stith Jeffrey L.
Published: October 2006

Airborne measurements of the effluents from the St. Augustine volcano obtained during a 10-day period of activity showed that aerosol was ejected at the rate of about 10
5
kilograms per second during brief eruptions (3 to 8 minutes). Steadier emissions contained much more water vapor and gaseous sulfur but less aerosol mass. A nuée ardente (glowing avalanche) produced by one eruption reached a maximum average speed of about 50 meters per second.
Paleogeographic Reconstructions of Coastal Aegean Archaeological Sites
Authors: Kraft John C. , Aschenbrenner Stanley E. , Rapp George
Published: October 2006

Many studies have been made of ancient Greek topography, some of the more recent ones based on modern techniques. However, most still ignore the subsurface dimension of coastal and other environments and hence fail to fully explain coastal and alluvial-colluvial processes, rates of change of geomorphology, and the effects of coastal change on humans. In this article subsurface geological analyses have been used to elucidate paleogeographic coastal settings of major archaeological sites around the Aegean Sea. Similar approaches could be applied in the Middle and Far East and elsewhere in the Mediterranean.
First Occurrence of the Garnet-Ilmenite Transition in Silicates
Authors: Liu Lin-Gun
Published: October 2006

Pyrope garnet (Mg
3
Al
2
Si
3
O
12
) has been found to transform to an ilmenite-type phase at a loading pressure between 240 and 250 kilobars and at about 1000° to 1400°C in a diamond-anvil press coupled with laser heating. The lattice parameters for the ilmenite-type phase of (Mg
.75
Al
.25
)(Si
.75
Al
.25
)O
3
are
a
0
= 4.755 ± 0.002 and
c
0
= 13.360 ± 0.005 angstroms. The zero-pressure volume change associated with the garnet-ilmenite transition is calculated to be –7.1 percent. This result verifies the prediction that pyrope garnet would transform to the ilmenite structure at high pressure first suggested in 1962 by Clark
et al.
and Ringwood.
Large-Scale Integration: What Is Yet to Come?
Authors: Noyce Robert N.
Published: October 2006

The rapid development of large-scale integrated circuits in the last two decades has revolutionized information handling. Higher levels of integration have been achieved principally by making the individual circuit elements smaller, but reduction of random defects and innovations in circuit design have also been important factors. Practical limits to the size of integrated circuits, such as those imposed by the use of photolithography to define the circuits, can be avoided by using other methods, such as solid-state diffusion or electron beams.

The prospects are that dimensions and defect densities will continue to be reduced while speed increases. Redundancy in circuits will lead to lower costs and higher levels of integration. As logic becomes more complex and applications narrower, the increased number of unique circuit designs needed tends to increase costs. The microprocessor was developed to answer this problem and will have a radical influence on future computing systems.
South American Geochronology: Radiometric Time Scale for Middle to Late Tertiary Mammal-Bearing Horizons in Patagonia
Authors: Marshall Larry G. , Pascual Rosendo , Curtis Garniss H. , Drake Robert E.
Published: October 2006

Radiometric (potassium-argon) age determinations for basalts and tuffs associated with middle to late Tertiary mammal-bearing horizons in Patagonia, southern Argentina, permit refinement of boundaries and hiatuses between beds of Deseadan (early Oligocene) through Friasian (middle to late Miocene) age. At two localities beds of Deseadan age are overlain by basalts, which gave dates of 33.6 and 35.4 million years ago; 34.0 million years ago is tentatively accepted as a terminal date for known Deseadan. At several localities beds of Colhuehuapian age are underlain by basalts, which gave dates ranging from 28.8 to 24.3 million years ago; 25.0 million years is tentatively taken as a basal age for known Colhuehuapian. The paleontological hiatus between known Deseadan and known Colhuehuapian is thus in the order of 9.0 million years. Two tuffs from the Santa Cruz Formation (Santacrucian) gave ages of 21.7 and 18.5 million years. Plagioclase and biotite concentrates of an ignimbrite from the Collón Curá Formation (Friasian) gave ages ranging from 15.4 to 14.0 million years.
Isoleucine Epimerization for Dating Marine Sediments: Importance of Analyzing Monospecific Foraminiferal Samples
Authors: King Kenneth , Neville Colleen
Published: October 2006

The rate of isoleucine epimerization in fossil planktonic foraminifera is strongly species-dependent. Alloisoleucine/isoleucine ratios of two species of the same age can vary by more than a factor of 2. This finding, in combination with the known temporal and spatial variability of foraminiferal assemblages, demonstrates the critical importance of basing geochronological studies of marine sediments on monospecific samples. One rapidly epimerizing species generates a calibration curve of potentially high precision for dating sediments between the ages of about 50,000 to 400,000 years.
Triacontanol: A New Naturally Occurring Plant Growth Regulator
Authors: Ries Stanley K. , Wert Violet , Sweeley Charles C. , Leavitt Richard A.
Published: October 2006

Alfalfa meal and chloroform extracts of the meal have increased the growth and yield of several plant species. A crystalline substance isolated from the active fraction of alfalfa meal increased the dry weight and water uptake of rice seedlings when sprayed on the foliage or applied in nutrient culture. The substance was identified as triacontanol by mass spectrometry. Sprays containing this compound also increased the growth of corn, and barley grown in soil. Authentic triacontanol produced a similar response over a wide range of concentrations on rice grown in nutrient cultures and tomatoes grown in soil.
Devon Island Ice Cap: Core Stratigraphy and Paleoclimate
Authors: Koerner R. M.
Published: October 2006

Valuable paleoclimatic information can be gained by studying the distribution of melt layers in deep ice cores. A profile representing the percentage of ice in melt layers in a core drilled from the Devon Island ice cap plotted against both time and depth shows that the ice cap has experienced a period of very warm summers since 1925, following a period of colder summers between about 1600 and 1925. The earlier period was coldest between 1680 and 1730. There is a high correlation between the melt-layer ice percentage and the mass balance of the ice cap. The relation between them suggests that the ice cap mass balance was zero (accumulation equaled ablation) during the colder period but is negative in the present warmer one. There is no firm evidence of a present cooling trend in the summer conditions on the ice cap. A comparison with the melt-layer ice percentage in cores from the other major Canadian Arctic ice caps shows that the variation of summer conditions found for the Devon Island ice cap is representative for all the large ice caps for about 90 percent of the time. There is also a good correlation between melt-layer percentage and summer sea-ice conditions in the archipelago. This suggests that the search for the northwest passage was influenced by changing climate, with the 19th-century peak of the often tragic exploration coinciding with a period of very cold summers.
Second Phases in Steel
Authors: Bandi W. R.
Published: October 2006

The present and future relationship between the metallurgical development of new steels and the determination of second-phase compounds in these steels is emphasized on the basis of recent developments in the quantitative determination of these phases. Results of the application of DTA-EGA methods are presented as an example of this analytical approach, and the method used to measure the amounts of gases evolved from the reactions of second-phase compounds with O
2
is described in detail. The DTA-EGA method has also revealed phases that had not been found earlier in steels. Smaller amounts of second-phase compounds can be more accurately determined by this method than by any other procedure. Examples are cited for the reaction of O
2
, H
2
, steam, and NH
3
with second-phase compounds in the isolated residue, and the use of these reactions for the determination of second phases is discussed. A disadvantage of the DTA-EGA method is that it is dependent on the quantitative chemical separation of the second phase from the matrix steel by one of several methods. The relative merits of isolating second-phase compounds by electrochemical dissolution, by dissolution in halogen and alcohols or aliphatic esters, and by use of dilute acids are discussed in terms of their effect on the DTA-EGA determination.
Phyllotaxis and the Fibonacci Series
Authors: Mitchison G. J.
Published: October 2006

The principal conclusion is that Fibonacci phyllotaxis follows as a mathematical necessity from the combination of an expanding apex and a suitable spacing mechanism for positioning new leaves. I have considered an inhibitory spacing mechanism at some length, as it is a plausible candidate. However, the same treatment would apply equally well to depletion of, or competition for, a compound by developing leaves, and could no doubt accommodate other ingredients.

The mathematical principles involved are clear when it is assumed that only two leaves (the contacts) position a new leaf. There is some experimental evidence for this assumption. Nonetheless, it is not a precondition for Fibonacci phyllotaxis, since a computer model shows that this pattern is generated even when many leaves contribute to inhibition at a given point. Indeed, the Fibonacci pattern seems to be a robust and stable mathematical phenomenon, a finding which goes some way to explaining its widespread occurrence throughout the plant kingdom.
High Rates of Vertical Crustal Movement near Ventura, California
Authors: Yeats Robert S.
Published: October 2006

Fission track, radiometric, and paleomagnetic age determinations in marine sedimentary rocks of the Ventura Basin make it possible to estimate the vertical components of displacement rates for the last 2 million years. The basin subsided at rates up to 9.5 ± 2.5 millimeters per year until about 0.6 million years ago, when subsidence virtually ceased. Since then, the northern margin of the basin has been rising at an average rate of 10 ± 2 millimeters per year, about the same rate as that based on the geodetic record north and west of Ventura since 1960 but considerably lower than the rate along the San Andreas fault at Palmdale since 1960.
Quarks with Unit Charge: A Search for Anomalous Hydrogen
Authors: Muller Richard A. , Alvarez Luis W. , Holley William R. , Stephenson Edward J.
Published: October 2006

Quarks of charge +1 and other anomalous hydrogen have been sought by using the 88-inch cyclotron at Berkeley as a high-energy mass spectrometer, with natural hydrogen and deuterium as the sources of ions. No quarks were observed, and limits were placed on their ratio to protons on the earth that vary from < 2 × 10
–19
for high masses (3 to 8.2 atomic mass units) to 10
–13
for the lowest masses (< 1/3 atomic mass unit).
Ecology and Evolution of Flowering Plant Dominance
Authors: Regal Philip J.
Published: October 2006

Birds and mammals are important seed dispersers and their diversification in the Cretaceous may have created niches for many plant specialists on scattered resources. Maintaining sexual recombination through wind pollination in such sparse populations is difficult, and so angiosperms with their sophisticated systems for insect pollination were favored in many critical situations.
Light and Stomatal Function: Blue Light Stimulates Swelling of Guard Cell Protoplasts
Authors: Zeiger E. , Hepler P. K.
Published: October 2006

Onion guard cell protoplasts swell when illuminated with blue light. The response is a 35 to 60 percent increase in volume and is dependent on potassium ion. Epidermal cell protoplasts do not swell under the same conditions. It is postulated that a membrane-bound blue photoreceptor mediates a direct response of guard cells to light.
Surface of Venus: Evidence of Diverse Landforms from Radar Observations
Authors: Malin Michael C. , Saunders R. Stephen
Published: October 2006

Recent radar images of the surface of Venus reveal a complex and varied terrain. By applying a set of simplifying assumptions about the nature of the surfaces returning the radar signal, it is possible to make a number of plausible interpretations. In one region on Venus, several circular features have the gross morphology of degraded impact craters. If they are indeed of impact origin, these features suggest that there exist on Venus areas which are ancient and where erosion or resurfacing has not been as intense or as pervasive as on the earth. In other regions there are intriguing features that may evidence active internal processes. One is a large trough-like depression (0°, 76°W; measuring 1400 by 150 by 2 kilometers) planimetrically suggestive of both the Valles Marineris on Mars and the East African Rift on the earth. Another feature, about 250 kilometers in diameter and of positive relief, includes an 80-kilometer-diameter circular depression at its summit, suggestive of a large volcanic construct. A third region, near 0°, 10°E, contains roughly parallel ranges of mountains separated by valley-like features, with relief varying from small isolated hills several hundred meters high to low ranges on the order of 1000 meters to large mountains approaching 2 kilometers in height. If Venus has a mobile crust similar to the earth's, these mountains may have been produced by compressional tectonics. These interpretations of the radar data indicate that Venus has been a geologically active planet which has developed diverse landforms and therefore is an exciting candidate for future exploration.
Photoassisted Electrolysis of Water by Visible Irradiation of a
p
-Type Gallium Phosphide Electrode
Authors: Tomkiewicz Micha , Woodall Jerry M.
Published: October 2006

Photoelectrolytic decomposition of water with visible irradiation is demonstrated in a cell made of
p
-type gallium phosphide as the cathode and platinum as the anode. A maximum energy conversion efficiency of 0.1 percent is achieved with an external bias of 1.3 volts. The stability of the electrode is demonstrated, and the results are discussed in terms of a composite energy diagram.
Mars: Microwave Detection of Carbon Monoxide
Authors: Kakar R. K. , Walters J. W. , Wilson W. J.
Published: October 2006

The 115-gigahertz microwave line of carbon monoxide has been detected in the spectrum of Mars. The measurement is sensitive to carbon monoxide between the surface and an altitude of approximately 50 kilometers in the martian atmosphere. This extends the altitude region to well above that previously sensed.
The Earth as a Seismic Absorption Band
Authors: Anderson Don L. , Kanamori Hiroo , Hart Robert S. , Liu Hsi-Ping
Published: October 2006

Attenuation of seismic waves indicates that the earth is not perfectly elastic. Dispersion accompanying absorption gives frequency-dependent "elastic" moduli, a fact that must be taken into account when inverting seismic data. Normal mode data are reinverted after correcting for absorption. The correction removes the discrepancy between body wave and free oscillation interpretations of earth structure.
Cleptoparasitism and Odor Mimetism in Bees: Do
Nomada
Males Imitate the Odor of
Andrena
Females?
Authors: Tengö Jan , Bergström Gunnar
Published: October 2006

Identical chemical compounds are present in the Dufour gland secretion of female
Andrena
bees and in the cephalic secretion of many male
Nomada
bees. Females of
Nomada
parasitize the nests of
Andrena.
Many
Nomada
species confine their attacks to a single host species. In two such host-parasite pairs,
Andrena haemorrhoa-Nomada bifida
and
Andrena carantonica-Nomada marshamella
, all -
trans
farnesyl hexanoate was found to be the totally dominant component in respective secretions. In two other pairs,
Andrena helvola-Nomada panzeri
and
Andrena clarkella-Nomada leucophthalma
, geranyl octanoate is the major component. This pairwise odor correspondence is discussed in relation to critical points of contact in the life cycles of host and parasite, male and female.
Dust Concentration in the Atmosphere of the Equatorial North Atlantic: Possible Relationship to the Sahelian Drought
Authors: Prospero Joseph M. , Nees Ruby T.
Published: October 2006

The concentration of insoluble mineral aerosol in the lower troposphere of the western equatorial North Atlantic Ocean has increased by a factor of 3 over the last decade. This increase may be related to the drought in the Sahelian zone of North Africa.
Voyaging Canoes and the Settlement of Polynesia
Authors: Finney Ben R.
Published: October 2006

Sailing trials with two reconstructed Polynesian double canoes indicate that these craft can make good a course to windward up to approximately 75° off the wind on long ocean voyages. This windward performance would have enabled Polynesians to exert a degree of control over their movements that would have been denied them had they only been able to sail or drift before wind and current. Indeed, without this windward sailing capacity there probably never would have been a Polynesian people today, for in a sense they are a product of their maritime technology. Had there been no great voyaging canoes, the settlement of Polynesia might have had to await the relatively late entry into the Pacific of the European navigators. But the Pacific was the scene of early innovation in weatherly sailing canoes, and as the European navigators "discovered" island after island, they were surprised to find that neolithic seafarers had preceded them into this vast ocean realm.
Desert Varnish: The Importance of Clay Minerals
Authors: Potter Russell M. , Rossman George R.
Published: October 2006

Desert varnish has been characterized by infrared spectroscopy, x-ray diffraction, and electron microscopy. It is a distinct morphological entity having an abrupt boundary with the underlying rock. Clay minerals comprise more than 70 percent of the varnish. Iron and manganese oxides constitute the bulk of the remainder and are dispersed throughout the clay layer.
Great Lakes Eutrophication: The Effect of Point Source Control of Total Phosphorus
Authors: Chapra Steven C. , Robertson Andrew
Published: October 2006

A mathematical model of the Great Lakes total phosphorus budgets indicates that a 1 milligram per liter effluent restriction for point sources would result in significant improvement in the trophic status of most of the system. However, because large areas of their drainage basins are devoted to agriculture or are urbanized, western Lake Erie, lower Green Bay, and Saginaw Bay may require non-point source controls to effect significant improvements in their trophic status.
Landsat, Computers, and Development Projects
Authors: Adrien Pierre-Marie , Baumgardner Marion F.
Published: October 2006

Data provided by earth-orbiting satellites and analyzed through specific computer techniques are rapidly providing policy-makers around the world with new information on the location and extent of their countries' renewable and nonrenewable resources. Development projects utilizing remote sensing technology are being supported, for example, by the Inter-American Development Bank, the World Bank, and other international funding agencies. The Inter-American Development Bank is financing a natural resources inventory of five countries in Central America, and this will require the application of remote sensing in the analysis of 33 Landsat images covering the area. Although the Landsat program remains experimental in nature, studies pertaining to its follow-on aspects will ensure continuation of the program so that developed and developing countries will be able to maintain better control of the management of their natural resources.
Winter Intrusions of the Loop Current
Authors: Molinari R. L. , Baig S. , Behringer D. W. , Maul G. A. , Legeckis R.
Published: October 2006

Sea-surface temperature data obtained from satellite and subsurface temperature data obtained from ships are used to determine the intrusion of the Loop Current extended considerably farther to the north during the last three winters than has been observed previously.
Carbon-14: Direct Detection at Natural Concentrations
Authors: Nelson D. E. , Korteling R. G. , Stott W. R.
Published: October 2006

The
14
C atoms naturally present in a piece of 19th-century wood have been detected directly by means of a tandem Van de Graaff accelerator used as a high-energy mass spectrometer. The
14
C ions were easily resolved from interfering ions with the use of a Δ
E
-
E
detector telescope (this telescope consists of a pair of detectors; one of them measures the specific ionization, Δ
E
, and the sum of the signals from both detectors gives the total energy for each ion,
E
T
). The technique offers a number of practical advantages.
Selection of Retapamulin, a Novel Pleuromutilin for Topical Use
Authors: Rittenhouse Stephen , Biswas Sanjoy , Broskey John , McCloskey Lynn , Moore Terrance , Vasey Sandra , West Joshua , Zalacain Magdalena , Zonis Rimma , Payne David
Published: October 2006

The in vitro activity of retapamulin was determined and compared to that of topical and community antibiotics. The MIC
90
s of retapamulin against
Staphylococcus aureus
and
Streptococcus pyogenes
were 0.12 μg/ml and 0.016 μg/ml, respectively. Retapamulin has a low propensity to select resistance and produces an in vitro postantibiotic effect.
Use of the Surgical Wound Infection Model To Determine the Efficacious Dosing Regimen of Retapamulin, a Novel Topical Antibiotic
Authors: Rittenhouse Stephen , Singley Christine , Hoover Jennifer , Page Roni , Payne David
Published: October 2006

The effect of topically applied retapamulin ointment was evaluated using various dosing regimens in the
Staphylococcus aureus
and
Streptococcus pyogenes
wound infection model. Retapamulin (1%, wt/wt) was efficacious using twice-daily (b.i.d.) applications for 4 or 5 days. These data underpinned the decision to evaluate 1% retapamulin b.i.d. in clinical trials.
Biochemical Characterization of the Interactions of the Novel Pleuromutilin Derivative Retapamulin with Bacterial Ribosomes
Authors: Yan Kang , Madden Lenore , Choudhry Anthony E. , Voigt Christine S. , Copeland Robert A. , Gontarek Richard R.
Published: October 2006

Retapamulin is a semisynthetic pleuromutilin derivative being developed as a topical antibiotic for treating bacterial infections of the skin. It is potent in vitro against susceptible and multidrug-resistant organisms commonly associated with bacterial skin infections. We report detailed mode of action studies demonstrating that retapamulin binds to the bacterial ribosome with high affinity, inhibits ribosomal peptidyl transferase activity, and partially inhibits the binding of the initiator tRNA substrate to the ribosomal P-site. Taken together, these data distinguish the mode of action of retapamulin from that of other classes of antibiotics. This unique mode of action may explain the lack of clinically relevant, target-specific cross-resistance of retapamulin with antibacterials in current use.
Emergence of a Novel Lamivudine-Resistant Hepatitis B Virus Variant with a Substitution Outside the YMDD Motif
Authors: Yatsuji Hiromi , Noguchi Chiemi , Hiraga Nobuhiko , Mori Nami , Tsuge Masataka , Imamura Michio , Takahashi Shoichi , Iwao Eiji , Fujimoto Yoshifumi , Ochi Hidenori , Abe Hiromi , Maekawa Toshiro , Tateno Chise , Yoshizato Katsutoshi , Suzuki Fumitaka , Kumada Hiromitsu , Chayama Kazuaki
Published: October 2006

Lamivudine is a major drug approved for treatment of chronic hepatitis B virus (HBV) infection. Emergence of drug-resistant mutants with amino acid substitutions in the YMDD motif is a well-documented problem during long-term lamivudine therapy. Here we report a novel lamivudine-resistant strain of HBV with an intact YMDD motif, which included an amino acid substitution, rtA181T, in the reverse transcriptase (RT) domain of HBV polymerase. The substitution also induced a unique amino acid substitution (W172L) in the overlapping hepatitis B surface (HBs) protein. The YMDD mutant strains were not detected even by using the sensitive peptide nucleic acid-mediated PCR clamping method. The detected nucleotide substitution was accompanied by the emergence of an additional nucleotide substitution that induced amino acid change (S331C) in the spacer domain. The rtA181T mutant strain displayed a threefold decrease in susceptibility to lamivudine in in vitro experiments in comparison with the wild type. In vivo analysis using human hepatocyte-chimeric mice confirmed the resistance of this mutant strain to lamivudine. We developed a method to detect this novel rtA181T mutation and a previously reported rtA181T mutation with the HBs stop codon using restriction fragment length polymorphism PCR and identified one patient with the latter pattern among 40 patients with lamivudine resistance. In conclusion, although the incidence is not high, we have to be careful regarding the emergence of lamivudine-resistant mutant strains with intact YMDD motif.
Impact of Sample Size on the Performance of Multiple-Model Pharmacokinetic Simulations
Authors: Tam Vincent H. , Kabbara Samer , Yeh Rosa F. , Leary Robert H.
Published: October 2006

Monte Carlo simulations are increasingly used to predict pharmacokinetic variability of antimicrobials in a population. We investigated the sample size necessary to provide robust pharmacokinetic predictions. To obtain reasonably robust predictions, a nonparametric model derived from a sample population size of ≥50 appears to be necessary as the input information.
Calcineurin Promotes Infection of the Cornea by
Candida albicans
and Can Be Targeted To Enhance Fluconazole Therapy
Authors: Onyewu Chiatogu , Afshari Natalie A. , Heitman Joseph
Published: October 2006

In an established
Candida albicans
murine keratitis model, combination therapy with ophthalmic preparations of fluconazole and cyclosporine A (CsA) demonstrated in vivo drug synergy and effectively resolved wild-type
C. albicans
infection more rapidly than monotherapy with either drug. Calcineurin, the target of CsA, was also found to contribute to pathogenicity.
Evaluation of the Activities of Pyrimethamine Analogs against
Plasmodium vivax
and
Plasmodium falciparum
Dihydrofolate Reductase-Thymidylate Synthase Using In Vitro Enzyme Inhibition and Bacterial Complementation Assays
Authors: Bunyarataphan Sasinee , Leartsakulpanich Ubolsree , Taweechai Supannee , Tarnchompoo Bongkoch , Kamchonwongpaisan Sumalee , Yuthavong Yongyuth
Published: October 2006

Pyrimethamine analogs were examined as potential agents against vivax malaria using a bacterial surrogate system carrying
Plasmodium vivax
dihydrofolate reductase-thymidylate synthase (PvDHFR-TS), in which the PvDHFR complemented chemically knocked out host dihydrofolate reductase. The system was initially tested with
P. falciparum
dihydrofolate reductase-thymidylate synthase and was found to have good correlation with the parasite-based system. The 50% inhibitory concentrations derived from PvDHFR-TS-dependent bacteria were correlated with their corresponding inhibition constants (

K
i

) from an enzyme inhibition assay, pointing to the likelihood that the potent enzyme inhibitors will also have potent antimalarial activities. Active compounds against both wild-type and S58R S117N (SP21) double-mutant
P. vivax
include analogs with structures which can avert a steric clash with the asparagine (S117N) side chain of the mutant, similar to those found for homologous
Plasmodium falciparum
mutants, raising the possibility that the same compounds can be developed against both types of antifolate-resistant malaria. This rapid and convenient drug screening system should be useful for development of new antifolates against
P. vivax
, for which a continuous culture system is not yet available.
Analysis of the Topology of
Vibrio cholerae
NorM and Identification of Amino Acid Residues Involved in Norfloxacin Resistance
Authors: Singh Anil Kumar , Haldar Rajen , Mandal Debabrata , Kundu Manikuntala
Published: October 2006

NorM, a putative efflux pump of
Vibrio cholerae
, is a member of the multidrug and toxic compound extrusion family of transporters. We demonstrate that NorM confers resistance to norfloxacin, ciprofloxacin, and ethidium bromide. Inactivation of
norM
rendered
V. cholerae
hypersensitive towards these fluoroquinolones. Multiple sequence alignment of members of its family identified several regions of high sequence conservation. The topology of NorM was determined using β-lactamase and chloramphenicol acetyltransferase fusions. The amino acid residues G
184
, K
185
, G
187
, P
189
, E
190
, G
192
, and G
195
in the periplasmic loops and L
381
, R
382
, G
383
, Y
384
, K
385
, and D
386
in the cytoplasmic loops, as well as all the acidic and cysteine residues of NorM, were mutated. Mutants G184V, G184W, K185I, P189S, E190K, and E190A lost the norfloxacin resistance-imparting phenotype characteristic of NorM. Mutants E124V, D155V, G187V, G187R, C196S, Y384H, Y384S, and Y384F exhibited partial resistance to norfloxacin. Mutants with replacements of G
184
or G
187
by A, K
185
by R, and E
190
by D retained the norfloxacin resistance phenotype of NorM. Analysis of the accumulation of norfloxacin in intact cells of
Escherichia coli
expressing NorM or its mutants in the presence or absence of carbonyl cyanide
m
-chlorophenylhydrazone supported the results obtained through susceptibility testing and argued in favor of NorM-mediated efflux as the determining factor in norfloxacin susceptibility in the genetically manipulated strains. Taken together, these results suggested that E
124
, D
155
, G
184
, K
185
, G
187
, P
189
, E
190
, C
196
, and Y
384
are likely involved in NorM-dependent norfloxacin efflux. Except for D
155
, C
196
, and Y
384
, all of these residues are located in periplasmic loops.
Duration of Outpatient Fecal Colonization Due to
Escherichia coli
Isolates with Decreased Susceptibility to Fluoroquinolones: Longitudinal Study of Patients Recently Discharged from the Hospital
Authors: Lautenbach Ebbing , Tolomeo Pam , Mao Xiangqun , Fishman Neil O. , Metlay Joshua P. , Bilker Warren B. , Nachamkin Irving
Published: October 2006

Among 10 subjects colonized with
Escherichia coli
isolates with reduced susceptibility to fluoroquinolones, the median duration of colonization following hospital discharge was 80 days (range, 8 to 172 days). Colonization was longer for isolates demonstrating organic-solvent tolerance than for isolates that were not organic-solvent tolerant (151 versus 29 days, respectively;
P
= 0.07) but was not associated with other resistance mechanisms, demographics, or antibiotic use.