bluuebunny/crossref_metadata_2025 huggingface dataset:
Multiplexed Lipid Dip‐Pen Nanolithography on Subcellular Scales for the Templating of Functional Proteins and Cell Culture
Authors: Sekula Sylwia , Fuchs Jeanette , Weg‐Remers Susanne , Nagel Peter , Schuppler Stefan , Fragala Joe , Theilacker Nora , Franzreb Matthias , Wingren Christer , Ellmark Peter , Borrebaeck Carl A. K. , Mirkin Chad A. , Fuchs Harald , Lenhert Steven
Published: September 2008

Molecular patterning processes taking place in biological systems are challenging to study in vivo because of their dynamic behavior, subcellular size, and high degree of complexity. In vitro patterning of biomolecules using nanolithography allows simplification of the processes and detailed study of the dynamic interactions. Parallel dip‐pen nanolithography (DPN) is uniquely capable of integrating functional biomolecules on subcellular length scales due to its constructive nature, high resolution, and high throughput. Phospholipids are particularly well suited as inks for DPN since a variety of different functional lipids can be readily patterned in parallel. Here DPN is used to spatially pattern multicomponent micro‐ and nanostructured supported lipid membranes and multilayers that are fluid and contain various amounts of biotin and/or nitrilotriacetic acid functional groups. The patterns are characterized by fluorescence microscopy and photoemission electron microscopy. Selective adsorption of functionalized or recombinant proteins based on streptavidin or histidine‐tag coupling enables the semisynthetic fabrication of model peripheral membrane bound proteins. The biomimetic membrane patterns formed in this way are then used as substrates for cell culture, as demonstrated by the selective adhesion and activation of T‐cells.
Plasmatechnik in der Photovoltaikindustrie
Authors: Frenck Hubert‐Joachim , Bauer Michael
Published: September 2008

Seit der Einführung des EEG in Deutschland haben alle Bereiche photovoltaischer Produkte einen ungeahnten Aufschwung genommen. Konventionelle, wasserbasierte Solarzellen haben gegenüber Dünnschichttechniken immer noch den größeren Marktanteil. Die Produktionskapazitäten im Bereich der Dünnschichttechniken wurden in der letzten Zeit aus verschiedenen Motivationen heraus stark ausgebaut. Gleichzeitig haben sich die Fertigungstechniken zur Herstellung von siliziumbasierten Solarzellen weiterentwickelt, wobei ein Trend zur Standardisierung unübersehbar ist. Sowohl bei der Herstellung von großflächigen Dünnschichtmodulen, wie auch bei der Prozessierung von einzelnen Wafern werden plasmabasierte Prozesse in einer Reihe von Varianten verwendet. Zur Anwendung kommen PECVD Verfahren sowohl wie PVD Verfahren. Die Bandbreite der mit plasmabasierten Prozessen hergestellten Schichten reicht von Schichten wie SiN, ITO oder ZnO bis hin zum amorphen Silizium. Wir stellen an ausgewählten Beispielen aus den oben genannten Bereichen sich ergebende Fragestellungen für die Maschinentechnik und den Anwender vor.
GenaueMessung von Durchfluss und Leckrate beliebiger Gase über einen weiten Bereich
Authors: Jitschin Wolfgang.
Published: September 2008

In vielen Anwendungen der Vakuumtechnik müssen Gasströme und Leckraten gemessen werden. Je nach Anwendung erfolgt die Angabe des Gasstroms in verschiedenen Einheiten, die hier eindeutig definiert werden. Dann werden Primärverfahren zur Gasstrommessung beschrieben, mit denen der Gasstrom entsprechend seiner Definition auf direktem Weg gemessen wird. Beispiele veranschaulichen die praktische Umsetzung der Messverfahren. Weiterhin werden fundamentale Strö‐ mungsnormale untersucht, nämlich dünne Blende und Venturi‐Rohr. Die Strömung durch diese Normale ist gut verstanden und der Zusammenhang zwischen Gasstrom und Drücken vorhersagbar. Somit erlauben diese Normale eine Gasstrommessung durch Rückführung auf eine Druckmessung.
Elektrische Antriebe für die Raumfahrt
Authors: Leiter Hans , Bock Dagmar , Böhrk Hannah , Auweter‐Kurtz Monika
Published: September 2008

In diesem Artikel werden elektrische Triebwerke für Satelliten, Raumsonden und bemannte Raumfahrzeuge vorgestellt, die mit Plasma‐ und Ionenstrahlgeräten zur Materialbearbeitung verwandt sind. Die Notwendigkeit möglichst hoher Strahlgeschwindigkeiten wird erklärt und die Grenzen konventioneller chemischer Antriebe werden aufgezeigt. Anschließend werden zwei wichtige elektrische Triebwerkstypen, thermische Lichtbogentriebwerke und Ionentriebwerke, in ihrer Funktion und ihren Anwendungen beschrieben. Beide Typen sind bereits erfolgreich im Weltraum im Einsatz. Abgeschlossen wird der Artikel durch eine Beschreibung eines Hybridantriebs, der sowohl das Lichtbogenprinzip nutzt als auch die HochfrequenzIonisation verwendet. Er wird als potenzieller Antrieb für eine bemannte Marsmission betrachtet.
Thesen und Trends – Mit funktionalen Oberflächen in die Zukunft
Authors: Bandorf Ralf , Diehl Wolfgang , Heckmann Ulrike , Kondruweit Simone , Pflug Andreas , Holeczek Harald , Metzner Martin , Klotzbach Udo , Leson Andreas , Zimmer Otmar
Published: September 2008

Funktionale Oberflächen sind der Schlüssel zu innovativen Produkten. Schon heute bestimmen sie sowohl im industriellen als auch im Endverbraucherbereich zunehmend Gebrauchseigenschaften, Lebensdauer und Preis der meisten Güter, ganz allgemein also denWert für den Kunden. In der vom BMBF geförderten Untersuchung “Produktionstechnik zur Erzeugung funktionaler Oberflächen” [1] ermittelten drei Fraunhofer‐Institute den aktuellen Stand der Produktionstechnologien im Bereich funktionaler Oberflächen, ihre Zukunftsperspektiven und den Forschungsbedarf. Die wesentlichen Ergebnisse sind in diesem Beitrag zusammengefasst. Den Bericht können Sie unter info@ist.‐ fraunhofer.de anfordern.
What is an Acceptable Re-Stricture Rate after Urethroplasty?
Authors: Andrich D.E. , Mundy A.R.
Published: September 2008

Objective:

To assess a single surgeon's re-stricture rate after urethroplasty in an unselected group of patients compared with a highly selected group of complex patients and so define a re-stricture rate that can be used for counselling patients preoperatively.

Patients:

In the 3-year period 2004–2007 the authors between them performed 554 urethral reconstructions and the senior author performed the 123 most complex cases. In the same 3-year period the senior author also performed 146 consecutive unselected urethral reconstructions in a separate unit alone. The results of these two sets of patients were compared.

Results:

In the combined unit the senior surgeon's overall re-stricture rate with complex cases was 11%. None occurred in the bulbar urethroplasty group and the re-stricture rate was the same in the primary cases and the revision cases. In the unselected group of patients the re-stricture rate was 4–11% and varied according to the location and complexity of the stricture.

Conclusions:

Case mix influences the results of surgery and can double the re-stricture rate from about 5% to about 10%. Bulbar urethroplasty has the lowest re-stricture rate. Penile urethral surgery for strictures of increasing length carries an increasingly high re-stricture rate. The re-stricture rate after transperineal repair of pelvic fracture urethral injuries is 5–10% again according to complexity. The surgery of posterior urethral strictures is an altogether different technical exercise which should be considered separately.
Long-Term Evaluation of Tension-Free Vaginal Tape (TVT) Outcomes for a UK Surgeon: Objective Assessment and Patient Satisfaction Questionnaires
Authors: Cresswell J. , Page T. , Thorpe A.C.
Published: September 2008

Objective:

To evaluate the complication rates and long-term results of tension-free vaginal tape (TVT) placement for a single surgeon, in terms of objective assessment and patient reported outcome.

Patients and methods:

Data are presented for 118 cases treated between 1998 and 2004. All patients had proven urodynamic stress incontinence (USI) and were asked to complete a postal symptom questionnaire at a median of 62 months post-procedure.

Results:

Mean duration of incontinence was 6.6 years, and 18.6% of patients had undergone previous incontinence surgery. Median hospital stay was 24 h. Complications were bladder perforation in 6.8%, failure to void 11%, haemorrhage 0.8% and late bladder, urethral and vaginal erosions in 3.4%, 0.8% and 1.7%, respectively. Overall continence rates were 86.4% (102/118) at a mean follow-up of 14.5 months. At a mean of 62 months post-operatively (range 31–102 months), questionnaire response rate was 54/118 (45.8%). 72.2% (30/54) of patients reported cure or improvement in symptoms, and 43/52 (82.7%) would recommend this procedure to a friend with similar symptoms.

Conclusion:

The outcomes reported compare favourably with published series and confirm the benefit of TVT as a procedure for USI. Patient satisfaction is high and morbidity low.
Predictors of Cancer on Repeat Prostate Biopsy: A Contemporary UK Series
Authors: Harris M.A. , Thomas M. , Harding C. , Chadwick D.
Published: September 2008

Objective:

The aim of our study was to review current rebiopsy practice across our cancer network and to develop evidence-based guidelines to assist clinicians and patients in taking the decision when to proceed to repeat prostate biopsy in a UK healthcare setting.

Methods:

We conducted case note review of patients who underwent more than one prostate biopsy over a 5-year period (2000–2005) within a single cancer network. Results: Multivariate logistic regression analysis demonstrated that the factors from the first biopsy associated with the diagnosis of cancer at rebiopsy were PINATYP (RR = 4.1, p < 0.05), ASAP (RR= 3.9, p< 0.05), HGPIN (RR= 3.8, p< 0.05), abnormal DRE (RR = 2.2, p< 0.05). Histological evidence of inflammation reduced the risk of cancer on rebiopsy in comparison with benign prostatic tissue. Age below 70 also resulted in a reduced risk. PSA doubling time correlated with a final diagnosis of cancer on Pearson correlation test (coefficient -.011). Only 43 patients (21.5%) had the average PSA measurement frequency within 6 months; however, the average PSA measurement frequency was not predictive of cancer diagnosis (between groups ANOVA, p> 0.05). 61 patients were diagnosed with prostate cancer. 38 patients (62%) received definitive local therapy with 13 patients (21%) receiving no immediate treatment.

Conclusions:

Our retrospective series has defined predictors of a cancer diagnosis on repeat biopsy in a UK population. The findings of this study will form the basis of our local guidelines for the time-being, but there is scope for a large prospective study utilizing the 10 or 12 core protocol recommended by NICE to ascertain the most appropriate frequency of PSA testing and the indications for repeat biopsy.
Polydimethylsiloxane in the Treatment of Sphincter Weakness Incontinence in Men with Spinal Cord Injury: Long-Term Follow-Up
Authors: Attar K.H. , Gurung P. , Hamid R. , Wood S. , Shah P.J.R.
Published: September 2008

Objective:

To assess the long-term effectiveness of polydimethylsiloxane (PDS, Macroplastique™) perisphincteric injections in treating male sphincter weakness incontinence (SWI) caused by spinal cord injury (SCI).

Patients and methods:

Fourteen male patients with SCI underwent PDS injection to the external urethral sphincter for SWI (mean age: 50.1 years; range: 32–79 years). A single surgeon at a specialist spinal injury unit managed all patients. Complete cure was defined as cessation of pad usage with no evidence of leakage on video cystometrogram (VCMG). Partial cure with improvement was defined as >50% reduction in the number of pads used with incontinence present on VCMG.

Results:

Twelve of the 14 patients had a mean (range) follow-up of 8.7 (6.8–10.5) years. One patient was lost to follow-up at 2 years and one other died at 19 months from an unrelated chest infection. Four patients required repeat injections. Cure was achieved in three patients (25%); two were completely dry at 7.5 years while one was partially dry at 8.7 years. The remaining nine patients required further interventions to achieve continence.

Conclusion:

The use of PDS can be contemplated as first-line treatment in SWI in SCI patients. The long-term effect can, however, be non-durable and repeat injections may be required.
A Quantitative Comparison of Four Current Portable Ultrasound Bladder Scanners
Authors: Small D.R. , Watson A. , McConnachie A.
Published: September 2008

Objective:

Portable bladder ultrasound is a necessary investigation in urology and other disciplines. Scanners image with or without bladder wall detection—others provide only numeric readout. In volunteers, we compared measurements from four current scanners.

Methods:

Bardscan, Verathon BVI3000, Verathon BVI6100 and Sonosite iLook15 were used with 28 healthy volunteers, with scanners in random order. Ordinary least squares regression modelled the measured volumes of each volunteer using each scanner. For each patient—scanner combination, the predicted volume from this model (corrected for the average bias of each scanner) represents the best estimate of the volume, and the difference between the measured bladder volume and the predicted volume was an estimate of the error of that measurement.

Results:

The iLook15 and Bardscan underpredict, and the BVI3000 and BVI6100 overpredict, relative to the average of the four scanners ( p< 0.05). The BVI3000 had slightly greater error variability than the others ( p = 0.051). Measurement error appears more variable for larger volumes.

Conclusion:

The two real-time imaging systems (the SonoSite iLook15 and the Bard-scan) tended to give lower volume estimates than the two systems from the same manufacturer (the BVI3000 and BVI6100). Of the two BVI scanners, the 6100 had markedly less variable error.
Critical amino acids for the 8(R)‐dioxygenase activity of linoleate diol synthase. A comparison with cyclooxygenases
Authors: Garscha Ulrike , Oliw Ernst H.
Published: September 2008

7,8‐Linoleate diol synthase (7,8‐LDS) of the take‐all fungus and cyclooxygenases can be aligned with ∼24% amino acid identity and both form a tyrosyl radical during catalysis. 7,8‐LDS was expressed in insect cells with native 8R‐dioxygenase and hydroperoxide isomerase activities. We studied conserved residues of 7,8‐LDS, which participate in cyclooxygenases for heme binding (His residues), hydrogen abstraction (Tyr), positioning (Tyr, Trp), and ionic binding of substrates (Arg). Site‐directed mutagenesis abolished 8R‐dioxygenase activities with exception of the putative distal histidine (His203Gln) and a tyrosine residue important for hydrogen bonding and substrate positioning (Tyr329Phe). The results demonstrate structural similarities between 7,8‐LDS and cyclooxygenases.
Recent advances in understanding the molecular basis of group BStreptococcusvirulence
Authors: Maisey Heather C. , Doran Kelly S. , Nizet Victor
Published: September 2008

Group BStreptococcuscommonly colonises healthy adults without symptoms, yet under certain circumstances displays the ability to invade host tissues, evade immune detection and cause serious invasive disease. Consequently, Group BStreptococcusremains a leading cause of neonatal pneumonia, sepsis and meningitis. Here we review recent information on the bacterial factors and mechanisms that direct host–pathogen interactions involved in the pathogenesis of Group BStreptococcusinfection. New research on host signalling and inflammatory responses to Group BStreptococcusinfection is summarised. An understanding of the complex interplay between Group BStreptococcusand host provides valuable insight into pathogen evolution and highlights molecular targets for therapeutic intervention.
First results from the Cassini radio occultations of the Titan ionosphere
Authors: Kliore Avydas J. , Nagy Andrew F. , Marouf Essam A. , French Richard G. , Flasar F. Michael , Rappaport Nicole J. , Anabttawi Aseel , Asmar Sami W. , Kahann Daniel S. , Barbinis Elias , Goltz Gene L. , Fleischman Don U. , Rochblatt David J.
Published: September 2008

The first four sets of radio occultations of the Titan's ionosphere were obtained by the Cassini spacecraft between March 2006 and May 2007. These occultations occurred at middle and high latitudes, at solar zenith angles from about 86° to 96°. The main ionospheric peak was seen, as expected from modeling and previous observations, near 1200 km, with a density of about 1–3 × 103 cm−3. A consistent ledge near 1000 km was also seen, and one of the polar observations found a significant (∼3 × 103 cm−3) layer in the region of 500–600 km. This layer also is seen in other observations with a density varying from about 0.7 to 1.7 × 103 cm−3, suggesting a variable production source (or sources) for this peak.
Enhancing the physical significance of rainfall breakpoints through two‐dimensional video distrometer data
Authors: Sansom John , Schönhuber Michael , Thomson Peter , Randeu Walter L.
Published: September 2008

The temporal resolution of any rainfall model limits the degree to which it can physically represent the rainfall process. The recently developed hidden semi‐Markov model (HSMM) of rainfall is a statistical model based on breakpoint data in which the progression of rainfall is well approximated by a succession of periods with steady rain rates. These periods are not of any fixed length, such as an hour, but can vary from being sub‐minute for brief heavy showers to being many days for the dry period between events. Since the breakpoint periods have a duration precision of the order of seconds, the HSMM can follow changes at that timescale and so provide a physical representation of rainfall. This inference fails if the breakpoint data themselves have no physical significance which raises the question concerning what occurs at a breakpoint to cause a sudden change in the rain rate. The hypothesis advanced was that a breakpoint occurs at a change in the (rain) drop‐size distribution (DSD) when the rate of rainfall also changes. The Wilcoxon statistic can be used to test for differences in distribution between two samples and time series of this statistic were extracted from data collected by the two‐dimensional video distrometer (2DVD) on the size, shape, speed, and timing of individual raindrops. Changes in the DSD were located at significant values of the Wilcoxon statistic and these locations compared to those of the breakpoints extracted from the same data sets. Over the 96 daily data sets, the median time gap between a significant Wilcoxon and a breakpoint was about 30 s, and Monte Carlo methods showed that for nearly half of the data sets the median time gaps would only be smaller for 1% of all random re‐distributions of the breakpoints. Thus the overall degree of the match between the significant Wilcoxon statistics and the breakpoints occurring by chance is negligible, and the hypothesis that breakpoints occur at DSD changes acceptable. Furthermore, a hierarchical view of the rainfall process is advanced in which the top levels can be attributed to the changing dynamics of the atmosphere while the breakpoint level is a reflection of the physical processes that form raindrops.
Estimating the summertime tropospheric ozone distribution over North America through assimilation of observations from the Tropospheric Emission Spectrometer
Authors: Parrington M. , Jones D. B. A. , Bowman K. W. , Horowitz L. W. , Thompson A. M. , Tarasick D. W. , Witte J. C.
Published: September 2008

We assimilate ozone and CO retrievals from the Tropospheric Emission Spectrometer (TES) for July and August 2006 into the GEOS‐Chem and AM2‐Chem models. We show that the spatiotemporal sampling of the TES measurements is sufficient to constrain the tropospheric ozone distribution in the models despite their different chemical and transport mechanisms. Assimilation of TES data reduces the mean differences in ozone between the models from almost 8 ppbv to 1.5 ppbv. Differences between the mean model profiles and ozonesonde data over North America are reduced from almost 30% to within 5% for GEOS‐Chem, and from 40% to within 10% for AM2‐Chem, below 200 hPa. The absolute biases are larger in the upper troposphere and lower stratosphere (UT/LS), increasing to 10% and 30% in GEOS‐Chem and AM2‐Chem, respectively, at 200 hPa. The larger bias in the UT/LS reflects the influence of the spatial sampling of TES, the vertical smoothing of the TES retrievals, and the coarse vertical resolution of the models. The largest discrepancy in ozone between the models is associated with the ozone maximum over the southeastern USA. The assimilation reduces the mean bias between the models from 26 to 16 ppbv in this region. In GEOS‐Chem, there is an increase of about 11 ppbv in the upper troposphere, consistent with the increase in ozone obtained by a previous study using GEOS‐Chem with an improved estimate of lightning NOx emissions over the USA. Our results show that assimilation of TES observations into models of tropospheric chemistry and transport provides an improved description of free tropospheric ozone.
D/H ratio during the northern polar summer and what the Phoenix mission might measure
Authors: Fisher David , Novak Robert , Mumma Michael J.
Published: September 2008

The Phoenix polar mission will land close to 68°N, 233°E in May 2008 at Ls ∼ 75 and operate 90 sols until Ls ∼ 125 with possible extension to Ls ∼ 142. Phoenix Meteorology (MET), Thermal and Evolved Gas Analyzer (TEGA) and Microscopy, Electrochemistry and Conductivity Analyzer (MECA) instrument packages will measure the air's temperature, water vapor concentration, ice crystal concentration and the water's stable isotope ratio D/H, and the D/H for the uppermost ground ice. This paper summarizes what is known about the seasonal cycle of atmospheric D/H and makes a theoretical connection between the atmospheric ratio and that expected from the ground ice that Phoenix will sample. A simple mixed cloud stable isotope model is used to show that the seasonal progress of D/H in the polar region cannot be used alone. It is argued that the seasonal cycle in D/H is explained by their being an interplay between multilatitudinal sources or reservoirs that have a range of reservoir D/H values. These reservoirs have different sizes and seasonal response times so that they release their water contributions at different times of the spring and summer and together explain most of the seasonal D/H observed by Mumma et al. (2003) and Novak et al. (2005). Phoenix observations from its high‐latitude vantage point during the summer and fall will add some atmospheric D/H values, temperature, water vapor concentration, and ice cloudiness data points that will constrain the various theoretical possibilities. The D/H of the ice recovered by Phoenix from the surface of the ground ice combined with the atmospheric D/H will suggest, whether the ground ice presently is a net receiver or supplier of water to the northern ice cap.
Dynamics of N removal over annual time periods in a suburban river network
Authors: Wollheim W. M. , Peterson B. J. , Thomas S. M. , Hopkinson C. H. , Vörösmarty C. J.
Published: September 2008

River systems are dynamic, highly connected water transfer networks that integrate a wide range of physical and biological processes. We used a river network nitrogen (N) removal model with daily temporal resolution to evaluate how elevated N inputs, saturation of the denitrification and total nitrate removal processes, and hydrologic conditions interact to determine the amount, timing and distribution of N removal in the fifth‐order river network of a suburban 400 km2 basin. Denitrification parameters were based on results from whole reach 15NO3 tracer additions. The model predicted that between 15 and 33% of dissolved inorganic nitrogen (DIN) inputs were denitrified annually by the river system. Removal approached 100% during low flow periods, even with the relatively low and saturating uptake velocities typical of surface water denitrification. Annual removal percentages were moderate because most N inputs occurred during high flow periods when hydraulic conditions and temperatures are less favorable for removal by channel processes. Nevertheless, the percentage of annual removal occurring during above average flow periods was similar to that during low flow periods. Predicted river network removal proportions are most sensitive to loading rates, spatial heterogeneity of inputs, and the form of the removal process equation during typical base flow conditions. However, comparison with observations indicates that removal by the river network is higher than predicted by the model at moderately high flows, suggesting additional removal processes are important at these times. Further increases in N input to the network will lead to disproportionate increases in N exports due to the limits imposed by process saturation.
Effects of bedrock groundwater on spatial and temporal variations in soil mantle groundwater in a steep granitic headwater catchment
Authors: Katsura Shin'ya , Kosugi Ken'ichirou , Mizutani Tasuku , Okunaka Suemi , Mizuyama Takahisa
Published: September 2008

We investigated processes of soil mantle groundwater generation in a granitic headwater catchment in central Japan. Two types of groundwater were observed: ephemeral‐type groundwater (EG), which developed in response to rainfall events and disappeared rapidly after the events ceased, and semiperennial‐type groundwater (SPG), which remained formed for more than several months. The groundwater level, chemistry, and temperature within the soil and bedrock layers indicated that the source of EG was rain or soil water, whereas the source of SPG was deep bedrock groundwater. The generation processes of soil mantle groundwater varied both spatially and temporally under the influence of the underlying bedrock. Whereas only EG was generated in upslope areas, bedrock groundwater continuously seeped into the soil layers in downslope areas to generate SPG. In middle‐slope areas, an increase in the bedrock groundwater level generated SPG in soil layers, but the SPG disappeared when the bedrock groundwater level fell. Our results indicate that bedrock is important in controlling soil mantle groundwater generation and water flow processes in headwater catchments and that direct measurements of bedrock conditions are vital for clarifying the roles of bedrock in these processes.
Tropospheric ozone distributions over Europe during the heat wave in July 2007 observed from infrared nadir spectra recorded by IASI
Authors: Eremenko M. , Dufour G. , Foret G. , Keim C. , Orphal J. , Beekmann M. , Bergametti G. , Flaud J.‐M.
Published: September 2008

First partial tropospheric ozone columns (0–6 km) derived from radiances observed by the IASI instrument aboard the MetOp‐A platform over Europe during summer 2007 are presented. They were retrieved using an altitude‐dependent regularization method. Comparison with measurements from balloon sondes shows excellent agreement. Space‐borne observations show large lower tropospheric ozone amounts over South‐Eastern Europe during the heat wave period, which are also displayed by simulations with a regional chemistry‐transport model CHIMERE.
Temperature response of Mars to Milankovitch cycles
Authors: Schorghofer Norbert
Published: September 2008

On Mars annual mean surface temperature near ±60° latitude varies predominately with precession and is not closely related to annual mean insolation. Based on the last few million years of orbital history, the precession cycle dominates in a narrow latitude range 54°–65°, in which the margins of the two ice‐rich permafrost layers in each hemisphere happen to lie, while mean annual temperature at other latitudes is controlled by the obliquity cycle. The phenomenon already exists on an airless uniform body in Mars orbit, where this latitude range shifts to 62°–74° on both hemispheres, and is closely related to temperature amplitude dependent reradiation into space.
Erosion of the dayside magnetosphere at Mercury in association with ion outflows and flux rope generation
Authors: Kidder A. , Winglee R. M. , Harnett E. M.
Published: September 2008

In preparation for the arrival of the MESSENGER spacecraft at Mercury, and to further understanding of the Mariner 10 and ground‐based observations, 3‐D multifluid simulations are used to predict Mercury's magnetospheric response to forcing from the solar wind. The model, which includes both heavy (Na+) and light (He+) ionospheric ion populations, predicts that solar wind access to Mercury's surface is highly asymmetric and dependent on the strength and direction of the interplanetary magnetic field (IMF). In particular, during southward IMF much of the dayside magnetic field can be eroded, and enhanced plumes of sodium ions (with geometry similar to ground‐based emission observations) outflow at high latitudes into the solar wind. Development of reconnection in association with flux ropes similar to those at Earth are seen but with a shorter time scale of development and a closer radial distance (3–5 RM).
Responses of summertime extreme wave heights to local climate variations in the East China Sea
Authors: Yong Huang , Baoshu Yin , Perrie William , Yijun Hou
Published: September 2008

We detected the responses of summertime extreme wave heights (Htop10, average of the highest 10% of significant wave heights in June, July and August) to local climate variations in the East China Sea by applying an empirical orthogonal function analysis to Htop10 derived from the WAVEWATCH‐III wave model driven by 6 hourly sea surface wind fields from ERA‐40 reanalysis over the period 1958–2002. Decreases in Htop10 in the northern East China Sea (Yellow Sea) correspond to attenuation of the East Asian Summer Monsoon, while increases in the south are primarily due to enhancement of tropical cyclone activities in the western North Pacific.
Effect of clouds on the calculated vertical distribution of shortwave absorption in the tropics
Authors: McFarlane Sally A. , Mather James H. , Ackerman Thomas P. , Liu Zheng
Published: September 2008

High vertical resolution profiles of cloud properties were obtained from cloud radars operated by the Atmospheric Radiation Measurement (ARM) program on the islands of Nauru and Manus in the Tropical Western Pacific (TWP). Broadband flux calculations using a correlated k‐distribution model were performed to estimate the effect of clouds on the total column and vertical distribution of shortwave absorption at these tropical sites. Sensitivity studies were performed to examine the role of precipitable water vapor, cloud vertical location, optical depth, and particle size on the shortwave (SW) column absorption. On average, observed clouds had little impact on the calculated total SW column absorption at the two sites, but a significant impact on the vertical distribution of SW absorption. Differences in the column amount, vertical profiles, and diurnal cycle of SW absorption at the two sites were due primarily to differences in cirrus cloud frequency.
Molecular hydrogen uptake by soils in forest, desert, and marsh ecosystems in California
Authors: Smith‐Downey Nicole V. , Randerson James T. , Eiler John M.
Published: September 2008

The mechanism and environmental controls on soil hydrogen (H2) uptake are not well understood but are essential for understanding the atmospheric H2 budget. Field observations of soil H2 uptake are limited, and here we present the results from a series of measurements in forest, desert, and marsh ecosystems in southern California. We measured soil H2 fluxes using flux chambers from September 2004 to July 2005. Mean H2 flux rates and standard deviations were −7.9 + −4.2, −7.6 + −5.3 and −7.5 + −3.4 nmol m−2 s−1 for the forest, desert, and marsh, respectively (corresponding to deposition velocities of 0.063 + −0.029, 0.051 + −0.036, 0.035 + −0.013 cm s−1). Soil profile measurements showed that H2 mixing ratios were between 3% and 51% of atmospheric levels at 10 cm and that the penetration of H2 into deeper soil layers increased with soil drying. Soil removal experiments in the forest demonstrated that the litter layer did not actively consume H2, the removal of this layer increased uptake by deeper soil layers, and the exposure of subsurface soil layers to ambient atmospheric H2 levels substantially increased their rate of uptake. Similar soil removal experiments at the desert site showed that extremely dry surface soils did not consume H2 and that fluxes at the surface increased when these inactive layers were removed. We present a model of soil H2 fluxes and show that the diffusivity of soils, along with the vertical distribution of layers that actively consume H2 regulate surface fluxes. We found that soil organic matter, CO2 fluxes, and ecosystem type were not strong controllers of H2 uptake. Our experiments highlight H2 diffusion into soils as an important limit on fluxes and that minimum moisture level is needed to initiate microbial uptake.
Simple approaches for measuring dry atmospheric nitrogen deposition to watersheds
Authors: Golden Heather E. , Boyer Elizabeth W. , Brown Michael G. , Elliott Emily M. , Lee Don Koo
Published: September 2008

Assessing the effects of atmospheric nitrogen (N) deposition on surface water quality requires accurate accounts of total N deposition (wet, dry, and cloud vapor); however, dry deposition is difficult to measure and is often spatially variable. Affordable passive sampling methods are available for estimating “hot spots” and spatial variations of gaseous dry N deposition (i.e., nitrogen dioxide (NO2) and ammonia (NH3)), though few viable methods for estimating the deposition from nitric acid (HNO3) gas using passive sampling techniques exist. We consider passive sampling approaches for assessing spatial patterns of dry atmospheric N deposition across watersheds. We describe a method for constructing an inexpensive passive sampler (for less than $12 per unit) for monitoring spatial variations in the magnitude of HNO3 in the atmosphere. We demonstrate the applicability of passive samplers for use in watershed biogeochemical research and water quality management through a review of previous applications and via our own case study of the South Korean peninsula.
On contemporaneous controls, unlikely outcomes, boxes and replacing the ‘Student’: Good statistical practice in pharmacology, problem 3
Authors: Lew M J
Published: September 2008

This paper is intended to assist pharmacologists to make the most of statistical analysis and avoid common errors. A scenario, in which an experimenter performed an experiment in two separate stages, combined the control groups for analysis and found some surprising results, is presented. The consequences of combined controls are discussed, appropriate display and analysis of the data are described, and an analysis of the likelihood of erroneous conclusions is made. Comparisons between data from separately conducted experimental series are hazardous when there is any possibility that the properties of the experimental units have changed between the series. Experiments that have been performed independently should be analyzed independently. Unlikely or surprising results should be treated with caution and a high standard of evidence should be required, and verification by repeated experiments should be performed and reported. Box and whisker plots contain more information than plots more commonly used to display for qualitative variables and should be used where the sample size is large enough (say, n5). In most biomedical experiments the observations are not random samples from large populations as assumed by conventional parametric analyses such as Student's t‐test, and so permutation tests, which do not lose their validity when a sampled population is non‐normal or when the data are not random samples, should frequently be used instead of Student's t‐tests.

British Journal of Pharmacology (2008) 155, 797–803; doi:10.1038/bjp.2008.350; published online 22 September 2008
The pharmacological challenge to tame the transient receptor potential vanilloid‐1 (TRPV1) nocisensor
Authors: Holzer P
Published: September 2008

The transient receptor potential vanilloid‐1 (TRPV1) cation channel is a receptor that is activated by heat (>42 °C), acidosis (pH<6) and a variety of chemicals among which capsaicin is the best known. With these properties, TRPV1 has emerged as a polymodal nocisensor of nociceptive afferent neurones, although some non‐neuronal cells and neurones in the brain also express TRPV1. The activity of TRPV1 is controlled by a multitude of regulatory mechanisms that either cause sensitization or desensitization of the channel. As many proalgesic pathways converge on TRPV1 and this nocisensor is upregulated and sensitized by inflammation and injury, TRPV1 is thought to be a central transducer of hyperalgesia and a prime target for the pharmacological control of pain. As a consequence, TRPV1 agonists causing defunctionalization of sensory neurones and a large number of TRPV1 blockers have been developed, some of which are in clinical trials. A major drawback of many TRPV1 antagonists is their potential to cause hyperthermia, and their long‐term use may carry further risks because TRPV1 has important physiological functions in the peripheral and central nervous system. The challenge, therefore, is to pharmacologically differentiate between the physiological and pathological implications of TRPV1. There are several possibilities to focus therapy specifically on those TRPV1 channels that contribute to disease processes. These approaches include (i) site‐specific TRPV1 antagonists, (ii) modality‐specific TRPV1 antagonists, (iii) uncompetitive TRPV1 (open channel) blockers, (iv) drugs interfering with TRPV1 sensitization, (v) drugs interfering with intracellular trafficking of TRPV1 and (vi) TRPV1 agonists for local administration.

British Journal of Pharmacology(2008)155, 1145–1162; doi:fn2; published online 22 September 2008
Low doses of α2‐adrenoceptor antagonists augment spinal morphine analgesia and inhibit development of acute and chronic tolerance
Authors: Milne B , Sutak M , Cahill C M , Jhamandas K
Published: September 2008

Background and purpose:

Ultra‐low doses of opioid receptor antagonists augment spinal morphine antinociception and block the induction of tolerance. Considering the evidence demonstrating functional and physical interactions between the opioid and α2‐adrenoceptors, this study investigated whether ultra‐low doses of α2‐adrenoceptor antagonists also influence spinal morphine analgesia and tolerance.

Experimental approach:

Effects of low doses of the competitive α2‐adrenoceptor antagonists—atipamezole (0.08, 0.8 ng), yohimbine (0.02, 2 ng), mirtazapine (0.02 ng) and idazoxan (0.08 ng) were investigated on intrathecal morphine analgesia, as well as acute and chronic morphine antinociceptive tolerance using the rat tail flick and paw pressure tests.

Key results:

At doses markedly lower than those producing α2‐adrenoceptor blockade, atipamezole, yohimbine, mirtazapine and idazoxan, prolonged the antinociceptive effects of morphine. When co‐administered with repeated acute spinal injections of morphine, all four agents blocked the induction of acute tolerance. Co‐injection of atipamezole with morphine for 5 days inhibited the development of tolerance in a chronic treatment paradigm. Spinal administration of atipamezole also reversed established antinociceptive tolerance to morphine as indicated by the restoration of morphine antinociceptive potency. The effects of atipamezole on spinal morphine tolerance were not influenced by treatment with 6‐hydroxydopamine.

Conclusions and implications:

Low doses of competitive α2‐adrenoceptor antagonists can augment acute morphine analgesia and block or reverse tolerance to spinal administration of morphine. These actions are interpreted in terms of their interaction with an opioid‐α2‐adrenoceptor complex, whose activity may have a function in the genesis of analgesic tolerance.

British Journal of Pharmacology(2008)155, 1264–1278; doi:10.1038/bjp.2008.353; published online 22 September 2008
Luteolin inhibits myelin basic protein‐induced human mast cell activation and mast cell‐dependent stimulation of Jurkat T cells
Authors: Kempuraj D , Tagen M , Iliopoulou B P , Clemons A , Vasiadi M , Boucher W , House M , Wolfberg A , Theoharides T C
Published: September 2008

Background and purpose:

Allergic inflammation and autoimmune diseases, such as atopic dermatitis, psoriasis and multiple sclerosis (MS), involve both mast cell and T‐cell activation. However, possible interactions between the two and the mechanism of such activations are largely unknown.

Experimental approach:

Human umbilical cord blood‐derived cultured mast cells (hCBMCs) and Jurkat T cells were incubated separately or together, following activation with myelin basic protein (MBP), as well as with or without pretreatment with the flavonoid luteolin for 15 min. The supernatant fluid was assayed for inflammatory mediators released from mast cells and interleukin (IL)‐2 release from Jurkat cells.

Key results:

MBP (10 μM) stimulates hCBMCs to release IL‐6, IL‐8, transforming growth factor (TGF)‐β1, tumour necrosis factor‐α (TNF‐α), vascular endothelial growth factor (VEGF), histamine and tryptase (n=6,P<0.05). Addition of mast cells to Jurkat cells activated by anti‐CD3/anti‐CD28 increases IL‐2 release by 30‐fold (n=3,P<0.05). MBP‐stimulated mast cells and their supernatant fluid further increase Jurkat cell IL‐2 release (n=3,P<0.05). Separation of mast cells and activated Jurkat cells by a Transwell permeable membrane inhibits Jurkat cell stimulation by 60%. Pretreatment of Jurkat cells with a TNF‐neutralizing antibody reduces IL‐2 release by another 40%. Luteolin pretreatment inhibits mast cell activation (n=3–6,P<0.05), Jurkat cell activation and mast cell‐dependent Jurkat cell stimulation (n=3,P<0.05).

Conclusions and implications:

Mast cells can stimulate activated Jurkat cells. This interaction is inhibited by luteolin, suggesting that this flavonoid may be useful in the treatment of autoimmune diseases.

British Journal of Pharmacology(2008)155, 1076–1084; doi:10.1038/bjp.2008.356; published online 22 September 2008
Differential role of tachykinin NK3 receptors on cholinergic excitatory neurotransmission in the mouse stomach and small intestine
Authors: De Man J G , De Winter B Y , De Schepper H U , Herman A G , Pelckmans P A
Published: September 2008

Background and purpose:

Tachykinin NK3 receptors are widely expressed in the mouse gastrointestinal tract but their functional role in enteric neuromuscular transmission remains unstudied in this species. We investigated the involvement of NK3 receptors in cholinergic neurotransmission in the mouse stomach and small intestine.

Experimental approach:

Muscle strips of the mouse gastric fundus and ileum were mounted in organ baths for tension recordings. Effects of NK3 agonists and antagonists were studied on contractions to EFS of enteric nerves and to carbachol.

Key results:

EFS induced frequency‐dependent tetrodotoxin‐sensitive contractions, which were abolished by atropine. The cholinergic contractions to EFS in the stomach were enhanced by the NK3 antagonist SR142801, but not affected by the NK3 agonist senktide or neurokinin B. The cholinergic contractions to EFS in the small intestine were not affected by SR142801, but dose‐dependently inhibited by senktide and neurokinin B. This inhibitory effect was prevented by SR142801 but not by hexamethonium. SR142801, senktide or neurokinin B did not induce any response per se in the stomach and small intestine and did not affect contractions to carbachol.

Conclusions and implications:

NK3 receptors modulate cholinergic neurotransmission differently in the mouse stomach and small intestine. Blockade of NK3 receptors enhanced cholinergic transmission in the stomach but not in the intestine. Activation of NK3 receptors inhibited cholinergic transmission in the small intestine but not in the stomach. This indicates a physiological role for NK3 receptors in mouse stomach contractility and a pathophysiological role in mouse intestinal contractility.

British Journal of Pharmacology (2008) 155, 1195–1203; doi:10.1038/bjp.2008.357; published online 22 September 2008
Intra‐ and extrarenal arteries exhibit different profiles of contractile responses in high glucose conditions
Authors: Nobe K , Nezu Y , Tsumita N , Hashimoto T , Honda K
Published: September 2008

Background and purpose:

The renal artery (RA) has been extensively investigated for the assessment of renal vascular function/dysfunction; however, few studies have focused on the intrarenal vasculature.

Experimental approach:

We devised a microvascular force measurement system, which allowed us to measure contractions of interlobar arteries (ILA), isolated from within the mouse kidney and prepared without endothelium.

Key results:

KCl (50 mM) induced similar force development in the aorta and RA but responses in the ILA were about 50% lower. Treatment of RA with 10 μMphenylephrine (PE), 10 nMU46619 (thromboxane A2analogue) or 10 μMprostaglandin F2αelicited a response greater than 150% of that induced by KCl. In ILA, 10 nMU46619 elicited a response that was 130% of the KCl‐induced response; however, other agonists induced levels similar to that induced by KCl. High glucose conditions (22.2 mMglucose) significantly enhanced responses in RA and ILA to PE or U46619 stimulation. This enhancement was suppressed by rottlerin, a calcium‐independent PKC inhibitor, indicating that glucose‐dependent, enhanced small vessel contractility in the kidney was linked to the activation of calcium‐independent PKC.

Conclusion and implications:

Extra‐ and intrarenal arteries exhibit different profiles of agonist‐induced contractions. In ILA, only U46619 enhanced small vessel contractility in the kidney, which might lead to renal dysfunction and nephropathy through reduced intrarenal blood flow rate. A model has been established, which will allow the assessment of contractile responses of intrarenal arteries from murine models of renal disease, including type 2 diabetes.

British Journal of Pharmacology(2008)155, 1204–1213; doi:10.1038/bjp.2008.365; published online 22 September 2008
Mono‐galloyl glucose derivatives are potent poly(ADP‐ribose) glycohydrolase (PARG) inhibitors and partially reduce PARP‐1‐dependent cell death
Authors: Formentini L , Arapistas P , Pittelli M , Jacomelli M , Pitozzi V , Menichetti S , Romani A , Giovannelli L , Moroni F , Chiarugi A
Published: September 2008

Background and purpose:

Maintenance of poly(ADP‐ribose) (PAR) polymers at homoeostatic levels by PAR glycohydrolase (PARG) is central in cell functioning and survival. Yet the pharmacological relevance of PARG inhibitors is still debated. Gallotannin, a complex mixture of hydrolysable tannins from oak gall, inhibits PARG but which of its constituents is responsible for the inhibition and whether the pharmacodynamic properties are due to its antioxidant properties, has not yet been established.

Experimental approach:

A structure–activity relationship study was conducted on different natural and synthetic tannins/galloyl derivatives as potential PARG inhibitors, using a novel in vitro enzymic assay. Cytotoxicity was assayed in cultured HeLa cells.

Key results:

Mono‐galloyl glucose compounds were potent inhibitors of PARG, with activities similar to that of ADP‐(hydroxymethyl) pyrrolidinediol, the most potent PARG inhibitor yet identified. When tested on HeLa cells exposed to the PAR polymerase (PARP)‐1‐activating compound 1‐methyl‐3‐nitro‐1‐nitrosoguanidine (MNNG), 3‐galloyl glucose weakly inhibited PAR degradation. Conversely, the more lipophilic, 3‐galloyl‐1,2‐O‐isopropylidene glucose, despite being inactive on the pure enzyme, efficiently prolonged the half‐life of the polymers in intact HeLa cells. Also, PARG inhibitors, but not radical scavengers, reduced, in part, cell death caused by MNNG.

Conclusions and implications:

Taken together, our findings identify mono‐galloyl glucose derivatives as potent PARG inhibitors, and emphasize the active function of this enzyme in cell death.

British Journal of Pharmacology (2008) 155, 1235–1249; doi:10.1038/bjp.2008.370; published online 22 September 2008