bluuebunny/crossref_metadata_2025 huggingface dataset:
A composite coating of calcium alginate and gelatin particles on Ti6Al4V implant for the delivery of water soluble drug
Authors: Xiao Junwu , Zhu Yingchun , Liu Yanyan , Zeng Yi , Xu Fangfang
Published: December 2008

A composite coating on Ti6Al4V implant was prepared from alginate and gelatin particles through a dip‐coating method to control the release of the water soluble drug gentamicin and improve the surface properties of the implant. Gentamicin was dissolved in the coating or bonded to gelatin particles through Schiff base reaction. The drug release experiments in vitro showed that about 10% of gentamicin was released within 0.5 h, the release lasted for 10 days, and the release from the composite coating was dependent on the pH value. The composite coating could induce the formation of apatite on the coating surface, which was fully covered after 7 days immersing in SBF solution. In addition, Ti6Al4V plate with the composite coating had excellent antibacterial activity against Staphylococcus aureus. All of the results provided the possibility that this composite coating might be applied as a controlled release system to deliver the water soluble drug, and as a bioactive, biodegradable layer on the bio‐inert implant surface to induce the formation of apatite and actively bond to the surrounding tissue in vivo. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
The protein level of hypoxia‐inducible factor‐1α is increased in the plateau pika (Ochotona curzoniae) inhabiting high altitudes
Authors: Li Hong‐Ge , Ren Yong‐Ming , Guo Song‐Chang , Cheng Long , Wang De‐Peng , Yang Jie , Chang Zhi‐Jie , Zhao Xin‐Quan
Published: December 2008

The plateau pika (Ochotona curzoniae) is a high hypoxia‐tolerant species living only at 3,000–5,000 m above sea‐level on the Qinghai‐Tibetan plateau. Hypoxia‐inducible factor‐1 (HIF‐1) is a key transcription factor that regulates a variety of cellular and systemic adaptations to hypoxia. To investigate how the plateau pika adapts to a high‐altitude hypoxic environment at the molecular level, we examined the expression pattern of the HIF‐1α protein in the pika by Western blot and immunohistochemical analysis. We found that HIF‐1α protein is expressed at a significantly high level in the pika, which is higher in most tissues (particularly in the lung, liver, spleen and kidney) of the plateau pika than that of mice living at sea‐level. Importantly, we found that the protein levels of HIF‐1α in the lung, liver, spleen and kidney of the pika were increased with increased habitat altitudes. We observed that the plateau pika HIF‐1α localized to the nucleus of cells by an immunostaining analysis, and enhanced HRE‐driven gene expression by luciferase reporter assays. Our study suggests that the HIF‐1α protein levels are related to the adaptation of the plateau pika to the high‐altitude hypoxic environment. J. Exp. Zool. 311A:134–141, 2009. © 2008 Wiley‐Liss, Inc.
Winter circulation weather types and hospital admissions for cardiovascular, respiratory and digestive diseases in Salamanca, Spain
Authors: de Pablo Fernando , Tomás Clemente , Rivas Soriano Luis , Diego Luisa
Published: December 2008

The aim of this study is to evaluate the possible associations between daily hospital admissions for cardiovascular, respiratory and digestive diseases in Salamanca (Spain) and weather conditions during the winters of 1995–2005. An objective daily air mass classification was performed by means of statistical analysis of ground‐level meteorological data. This afforded seven main circulation weather types (CWTs) for the cold period, and the frequency distributions of these types and their meteorological characteristics were analysed.

A summary of the main characteristics of the hospital admission series and their distribution over the 10 years studied, together with the frequency distributions of the different diseases classified by ages, the average number of the hospital admissions for each day of week, type of disease and sex, is given. In addition, a comparison between air mass classification and hospital admissions was made using an admission index (AI), for each disease. Significant increases in hospital admissions for the cardiovascular AI were evident 24–48 h after a day characterized by an anticyclonic air mass, 4–5 days after a day characterized by a westerly air mass and 6–7 days after an easterly flow. For the respiratory AI, an increase was observed 2–3 days after a cyclonic situation, 4 days after a northeasterly situation, while for days characterized by southwesterly air masses no delay was observed. These results indicate that the effects of weather conditions on hospital admissions tend to occur some days after exposure. Copyright © 2008 Royal Meteorological Society
Application of centrifugal partition chromatography coupled with evaporative light scattering detection for the isolation of saikosaponins‐a and ‐c from Bupleurum falcatum roots
Authors: Yoon Kee Dong , Kim Jinwoong
Published: December 2008

Centrifugal partition chromatography (CPC) coupled with evaporative light scattering detection (ELSD) was applied to separate saikosaponins‐a and ‐c preparatively from Bupleurum falcatum roots. The two‐phase solvent system composed of ethyl acetate/n‐butanol/methanol/water (15:1:3:15 by volume) was used to yield saikosaponins‐a (36.1 mg) and ‐c (28.7 mg) from 370 mg of saponin‐rich extract. The purities of isolated compounds were 96.6 and 97.3% for saikosaponins‐a and ‐c, respectively. Structure identification of these compounds was accomplished by comparison of spectroscopic data of ESI‐MS, 1H NMR, and 13C NMR with those of previously reported values.
Neutral polar methacrylate‐based monoliths for normal phase nano‐LC and CEC of polar species including N‐glycans
Authors: Zhong Hengwen , El Rassi Ziad
Published: December 2008

Neutral diol methacrylate‐based monoliths were developed for normal phase chromatography (NPC) and NP‐CEC of polar compounds including N‐glycans. Four different diol methacrylate‐based monoliths were synthesized via the copolymerization of a functional monomer using either glyceryl monomethacrylate (GMM) or glycidyl methacrylate (GMA) and a crosslinker either ethylene dimethacrylate (EDMA) or trimethylolpropane trimethacrylate (TRIM). While the GMM‐based monoliths yield in one reaction step polar diol methacrylate monoliths that are ready for use in NPC or NP‐CEC, the GMA‐based monoliths required a postmodification with hot sulfuric acid to convert the epoxy functions into diols before use in NPC or NP‐CEC. All the four monoliths are neutral and void of fixed charges on their surfaces but yet exhibited relatively strong EOF in NP‐CEC. The EOF is attributed to the adsorption of ions from the mobile phase thus forming the electric double layer necessary for producing a bulk mobile phase flow. Under the same in situ copolymerization conditions of GMM or GMA with either EDMA or TRIM, the GMM–EDMA monolith was the best choice in terms of retention, separation efficiency, EOF velocity in CEC and linear flow velocity in Nano‐LC.
Use of the Rotation Vector in Brownian Dynamics Simulation of Transient Electro‐Optical Properties
Authors: Evensen Tom Richard , Naess Stine Nalum , Elgsaeter Arnljot
Published: December 2008

We have recently developed a new singularity‐free algorithm for Brownian dynamics simulation of free rotational diffusion. The algorithm is rigorously derived from kinetic theory and makes use of the Cartesian components of the rotation vector as the generalized coordinates describing angular orientation. Here, we report on the application of this new algorithm in Brownian dynamics simulations of transient electro‐optical properties. This work serves two main purposes. Firstly, it demonstrates the integrity of the new algorithm for BD‐simulations of the most common transient electro‐optic experiments. Secondly, it provides new insight into the performance of the new algorithm compared to algorithms that make use of the Euler angles. We study the transient electrically induced birefringence in dilute solutions of rigid particles with anisotropic polarization tensor in response to external electric field pulses. The use of both one single electric pulse and two electric pulses with opposite polarity are being analyzed. We document that the new singularity‐free algorithm performs flawlessly. We find that, for these types of systems, the new singularity‐free algorithm, in general, outperforms similar algorithms based on the Euler angles. In a wider perspective, the most important aspect of this work is that it serves as an important reference for future development of efficient BD‐algorithms for studies of more complex systems. These systems include polymers consisting of rigid segments with single‐segment translational–rotational coupling, segment–segment fluid‐dynamic interactions and holonomic constraints.

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Atypical Rheumatoid Nodules: A Possible Precursor to a Rheumatoid Variant in a Rheumatoid-Factor-Negative Patient. Case Report
Authors: Kim Sharon , Parker Wendy L. , Beckenbaugh Robert D.
Published: December 2008

Subcutaneous nodules occur in approximately 20–25% of rheumatoid factor (RF)-positive rheumatoid patients. In this paper, we present a unique case of a 47-year-old healthy RF-negative woman with a 3-year history of necrobiotic nodules over the dorsum of her hands, extensor forearms, and lower extremities. This may represent an atypical presentation or a new rheumatoid variant.
MR Arthrography of the Wrist: Controversies and Concepts
Authors: Maizlin Zeev V. , Brown Jacqueline A. , Clement Jason J. , Grebenyuk Julia , Fenton David M. , Smith Donna E. , Jacobson Jon A.
Published: December 2008

Magnetic resonance arthrography (MRA) has become the preferred modality for imaging patients with internal derangement of the wrist. However, several aspects of MRA use need to be clarified before a standardized approach to the imaging of internal derangement of the wrist can be developed. The objective of the study is to evaluate the efficiency of different magnetic resonance (MR) sequences in the detection of lesions of the triangular fibrocartilage complex (TFCC) and scapholunate and lunotriquetral ligaments on direct MRA. Thirty-one consecutive direct magnetic resonance arthrographic examinations of the wrist using a wrist surface coil were performed for the assessment of the TFCC and intrinsic ligaments on a 1.5-T MR imaging system (Signa; 16 channel, Excite, GE Healthcare, Milwaukee, WI, USA). All patients had wrist pain, and in six cases, there was associated clinical carpal instability. The presence, location, and extent of TFCC, scapholunate ligament (SLL), and lunotriquetral ligament (LTL) lesions on T1 fat-saturated, multiplanar gradient recalled (MPGR) and short tau inversion recovery (STIR) images were identified, compared, and analyzed. Forty-one lesions of the TFCC, SLL, and LTL were visualized on contrast-sensitive (T1 fat-saturated) images in 23/31 (74.2%) patients. Twenty-one lesions of the TFCC and intrinsic ligaments were visualized on noncontrast-sensitive (MPGR and STIR) images (15 tears of the TFCC and six tears of the SLL and LTL). All of these lesions were seen on T1 fat-saturated images; 48.8% (20/41) lesions seen on T1 fat-saturated images (eight tears of TFCC and 12 tears of SLL and LTT) were not seen on MPGR and/or STIR images. Superior contrast resolution, joint distention, and the flow of contrast facilitate the diagnosis of lesions of the TFCC and intrinsic ligaments on contrast-sensitive sequences making MRA the preferred modality for imaging internal derangements of the wrist. Little agreement exists regarding the value and location of perforations of the intrinsic ligaments given that both traumatic and degenerative perforations may be symptomatic. Noncommunicating defects of the ulnar attachments of the triangular fibrocartilage (TFC), tears of the dorsal segment of the SLL, and defects at the lunate attachment of the SLL have a higher likelihood of being symptomatic and caused by trauma rather than by degenerative perforation. Although no consensus exists, it would appear that most arthrographies should be started with a radiocarpal injection. Injection into the distal radioulnar joint should be added if no communicational defects are visualized following radiocarpal injection in patients with ulnar-sided wrist pain.
The New Era of Flash Sterilization
Authors: Carlo Arlene
Published: December 2008

Flash sterilization was developed for use in the or for emergent need and immediate use of an instrument that was dropped on the floor, forgotten, or unanticipated. Issues and concerns regarding flash sterilization practice run the gamut from overuse to misuse to increased risk for infection transmission to increased costs for the health care facility. Serious consequences of surgical infection and national demands for patient safety highlight the need for added vigilance in the practices of flash sterilization. Today, state of the art products and equipment can help address some of the challenges historically associated with the flash sterilization process. AORN J 86 (July 2007) 58–68. © AORN, Inc, 2007.
How Quickly are We Treating Muscle Invasive Bladder Cancer? Trends over a 17 Year Period
Authors: Mantle M. , Dickinson A. J. , Moody M. , Cox R.
Published: December 2008

Objective:

Our aim was to measure the time from presentation to definitive treatment for muscle invasive bladder cancer in the South West Region. This was compared with previous audits of waiting times over the past 17 years. Methods: A retrospective survey was carried out in each of the hospitals in the South West Region, to assess the interval between referral and definitive treatment of all new cases of muscle invasive bladder cancer in 2006. This was compared to the same data for 1989, 1993 [Dickinson AJ, Howe K, Bedford C, Sanders T, Prentice A, Sibley GNA. A retrospective study of the investigation and management of muscle-invasive bladder cancer in the South West Region. BJU 1996;77:70–75] and 1999.

Results:

A total of 153 patients were identified. 118 (77%) underwent immediate definitive treatment. Median delay to definitive treatment was 102 days, compared with 114, 96 and 101 days in 1989, 1993 and 1999 respectively. Median delay between TURBT and definitive treatment had increased to 70 days in 2006 compared with 55, 44 and 54 days in the previous years studied.

Conclusions:

The waits for initial cystoscopy and TURBT, both of which are governed by cancer wait targets, have come down over the last 17 years. However the subsequent delay from TURBT to definitive treatment has lengthened with no change in total time to treatment. Reasons might include TURBT being used as the stop the clock treatment, delay surrounding an increase in tertiary referrals and a general increase in workload.
Cohomologically triangulated categories II
Authors: Baues H.-J. , Muro F.
Published: December 2008

A cohomologically triangulated category is an additive categoryAtogether with a translation functortand a cohomology class Δ ∈H3(A,t) such that any good translation track category representing Δ is a triangulated track category. In this paper we give purely cohomological conditions on Δ which imply that (A,t,Δ) is a cohomologically triangulated category, avoiding the use of track categories. This yields a purely cohomological characterization of triangulated cohomology classes.
Role of microbiological studies in management of peritonsillar abscess
Authors: Repanos C , Mukherjee P , Alwahab Y
Published: December 2008

Introduction:

Peritonsillar abscess (quinsy) is one of the most common ENT emergencies. A 2002 UK audit of quinsy management revealed that an average ENT department treated 29 cases annually; the most common treatment was needle aspiration with intravenous antibiotics, and culture of the aspirate was often performed routinely. The aims of our study were to evaluate the value of routine culture of quinsy aspirates, and to establish whether the information thus gained was clinically useful.

Methods:

We examined the notes of patients admitted with quinsy to two hospitals in south-west England, from January 1998 to January 2004 in one hospital and from January 1995 to January 2005 in the other. A total of 577 cases was found. Aspirated pus had been sent for culture in 119 (21 per cent). These cases were examined in more detail.

Results:

Of the 119 patients, 78.2 per cent (93/119) were treated with either a cephalosporin or penicillin, plus metronidazole. Streptococcal species were cultured in 43.7 per cent (52/119) and anaerobes in 23.5 per cent (28/119; of these cultures, 5.9 per cent (7/119) were pure anaerobes only). All the anaerobes were sensitive to metronidazole. One of the 119 cultures, growing aerobic bacteria, was resistant to penicillin; however, this patient improved clinically on a combination of penicillin and metronidazole. No patients had their treatment changed because of culture results.

Conclusions:

There appears to be no need to routinely culture quinsy aspirates, based upon our findings (of 16 hospital years) and previous studies (which found no recorded episodes of treatment change as a result of culture sensitivities). The combination of penicillin or a cephalosporin, plus metronidazole appeared to be theoretically effective in 99.2 per cent (118/119) of our specimens; this finding is supported by other studies. However, the rare but potentially life-threatening complications of quinsy must be recognised.
Managing workflow in treatment planning using standard spreadsheet software
Authors: Vaarkamp J. , Hamilton C.S. , Escreet M. , Percy C.
Published: December 2008

Aims: Recent years have seen an expansion of UK radiotherapy treatment capacity with a drive to reduce radiotherapy waiting times. Consequently, the time available for planning patients is decreasing. In this context, management of treatment planning workflow in the Princess Royal Hospital is described and monthly planning times are presented from September 2003 onwards.

Materials and Methods: After patients are imaged, patient name, unit number and appointments are available to the planning spreadsheet via a link to the radiotherapy information system. The planning spreadsheet is in descending order of appointment date. Treatment planning staff select the first available task, taking account of individual competencies. At plan completion, the patient record is moved to the completed list.

Results: Since September 2003, patient numbers through treatment planning steadily increased from around 90 a month to about 130 currently. Planning times decreased from 11 to 7 workdays.

Conclusions: Workflow through treatment planning is indirectly managed and the approach allows for day-to-day staffing fluctuations and competency levels. There is instant information on planning status for all patients throughout the department, building up a record as part of the work process. Bottlenecks and staff training needs can be analysed by reviewing the historic patient workload.
Survival and proliferative roles of erythropoietin beyond the erythroid lineage
Authors: Noguchi Constance Tom , Wang Li , Rogers Heather M. , Teng Ruifeng , Jia Yi
Published: December 2008

Since the isolation and purification of erythropoietin (EPO) in 1977, the essential role of EPO for mature red blood cell production has been well established. The cloning of theEPOgene and production of recombinant human EPO led to the widespread use of EPO in treating patients with anaemia. However, the biological activity of EPO is not restricted to regulation of erythropoiesis. EPO receptor (EPOR) expression is also found in endothelial, brain, cardiovascular and other tissues, although at levels considerably lower than that of erythroid progenitor cells. This review discusses the survival and proliferative activity of EPO that extends beyond erythroid progenitor cells. Loss of EpoR expression in mouse models provides evidence for the role of endogenous EPO signalling in nonhaematopoietic tissue during development or for tissue maintenance and/or repair. Determining the extent and distribution of receptor expression provides insights into the potential protective activity of EPO in brain, heart and other nonhaematopoietic tissues.
Massive, low‐temperature hydrothermal flow from a basaltic outcrop on 23 Ma seafloor of the Cocos Plate: Chemical constraints and implications
Authors: Wheat C. Geoffrey , Fisher Andrew T.
Published: December 2008

Systematic variations in pore water chemical and thermal profiles from sediment gravity cores indicate the presence of a “cool” (10–20°C) ridge‐flank hydrothermal system within basement surrounding Dorado outcrop, a small basaltic edifice on 23 Ma seafloor of the Cocos Plate. Dorado outcrop is located within a 14,500‐km2 region of cool seafloor, where 60–90% of the lithospheric heat is removed advectively. Pore water chemical profiles from sediments on and near Dorado outcrop indicate a range of diffusive, advective, and diagenetic influences, including evidence for upward fluid seepage at up to several meters per year. The chemical composition of fluid that discharges from Dorado outcrop is only slightly different from that of bottom seawater. Pore water nitrate and geological constraints suggest a minimum volumetric flux per unit width of basement of 1800 m3 a−1 cm−1 and a total seawater flow through Dorado outcrop of ∼3000 kg a−1. This flow rate is orders of magnitude greater than that estimated from Baby Bare outcrop, a similarly sized basement edifice on younger seafloor on the eastern flank of the Juan de Fuca Ridge. The nearest likely basement recharge site is Tengosed Seamount located ∼20 km away. Calculated rates for the specific discharge at Dorado outcrop are consistent with young 14C ages, suggesting a residence time in basement no greater than a few hundred years. If the fluid exiting from Dorado outcrop is characteristic of ridge‐flank hydrothermal circulation in general (cool, relatively unaltered), these systems can have an important influence on global geochemical budgets for many solutes (e.g., chloride, magnesium, sulfate, potassium, lithium, boron, silica, phosphate, manganese, and iron) because the rate of fluid discharge is so large. Ridge flank fluids having the same composition of fluid exiting Dorado outcrop also may contribute to subseafloor microbial processes within basaltic basement and the overlying sediment, and suggest that oxidation reactions within basaltic crust can continue well beyond 10 Ma in some settings.
Estimation of phytoplankton loss rate by remote sensing
Authors: Zhai Li , Platt Trevor , Tang Charles , Dowd Mike , Sathyendranath Shubha , Forget Marie‐Hélène
Published: December 2008

A method is presented for estimation of seasonally‐varying, total loss rate of phytoplankton from time series of satellite‐derived phytoplankton biomass data. The loss is calculated as the difference between the (modelled) rate of photosynthesis and the observed, realized rate of change of phytoplankton biomass. A Monte Carlo procedure is used to recover the loss rates. The (biomass‐normalized) total loss rate shows a seasonal cycle with values ranging from 0.5 to 3 mg C (mg Chl)−1 h−1 and shows an abrupt shift during the spring bloom. On the other hand, the absolute loss rate increases during blooms, a consequence of the increase in the biomass. The normalized total loss rate can be further expressed as a time‐varying fraction of the assimilation number. The fraction lies in the range from 0.2 to 0.8. During the increasing (decreasing) phase of phytoplankton blooming, the ratio of growth to total loss increases (decreases), such that this ratio may have value as an ecological indicator for blooms.
Extent of Hadley circulations in dry atmospheres
Authors: Korty Robert L. , Schneider Tapio
Published: December 2008

The subtropical terminus of the Hadley circulation is interpreted as the latitude poleward of which vertical wave activity fluxes (meridional eddy entropy fluxes) become sufficiently deep to reach the upper troposphere. This leads to a sign change of the upper‐tropospheric divergence of meridional wave activity fluxes (convergence of meridional eddy angular momentum fluxes) and marks the transition from the tropical Hadley cell to the extratropical Ferrel cell. A quantitative formulation for determining the depth of vertical wave activity fluxes and thus the terminus of the Hadley circulation is proposed based on the supercriticality, a measure of the slope of isentropes. The supercriticality assumes an approximately constant value at the terminus of the Hadley circulation in a series of simulations with an idealized dry general circulation model. However, it is unclear how to generalize this supercriticality‐based formulation to moist atmospheres.
Strong tremor near Parkfield, CA, excited by the 2002 Denali Fault earthquake
Authors: Peng Zhigang , Vidale John E. , Creager Kenneth C. , Rubinstein Justin L. , Gomberg Joan , Bodin Paul
Published: December 2008

We show clear evidence of non‐volcanic tremor triggered by 2002 Mw7.8 Denali Fault earthquake near Parkfield. Triggered tremor is identified as bursts of high‐frequency (∼2–8 Hz), non‐impulsive seismic energy whose envelope is coherent among many stations and has the same periodicity as the passing surface waves. The tremor originates from at least three hypocenters near the San Andreas fault with differing frictional regimes, two in the creeping section and the other where the San Andreas is transitional between creeping and locked. All the sources originate below the seismogenic zone, suggesting that transitional frictional properties are necessary conditions for tremor generation. Tremor is excited by the Love waves when the San Andreas is sheared in a right‐lateral sense, encouraging slip, and is absent when the San Andreas is sheared in a left‐lateral sense, consistent with a simple frictional response to the driving stress.
Tailward flow of energetic neutral atoms observed at Venus
Authors: Galli A. , Fok M.‐C. , Wurz P. , Barabash S. , Grigoriev A. , Futaana Y. , Holmström M. , Ekenbäck A. , Kallio E. , Gunell H.
Published: December 2008

The Analyzer of Space Plasma and Energetic Atoms (ASPERA‐4) experiment on Venus Express provides the first measurements of energetic neutral atoms (ENAs) from Venus. The results improve our knowledge on the interaction of the solar wind with a nonmagnetized planet and they present an observational constraint to existing plasma models. We characterize the tailward flow of hydrogen ENAs observed on the nightside by providing global images of the ENA intensity. The images show a highly concentrated tailward flow of hydrogen ENAs tangential to the Venus limb around the Sun's direction. No oxygen ENAs above the instrument threshold are detected. The observed ENA intensities are reproduced with a simple ENA model within a factor of 2, indicating that the observed hydrogen ENAs originate from shocked solar wind protons that charge exchange with the neutral hydrogen exosphere.
Titan's winter polar vortex structure revealed by chemical tracers
Authors: Teanby N. A. , de Kok R. , Irwin P. G. J. , Osprey S. , Vinatier S. , Gierasch P. J. , Read P. L. , Flasar F. M. , Conrath B. J. , Achterberg R. K. , Bézard B. , Nixon C. A. , Calcutt S. B.
Published: December 2008

The winter polar vortex on Saturn's largest moon Titan has profound effects on atmospheric circulation and chemistry and for the current northern midwinter season is the major dynamical feature of Titan's stratosphere and mesosphere. We use 2 years of observations from Cassini's composite infrared spectrometer to determine cross sections of five independent chemical tracers (HCN, HC3N, C2H2, C3H4, and C4H2), which are then used to probe dynamical processes occurring within the vortex. Our results provide compelling evidence that the vortex acts as a strong mixing barrier in the stratosphere and mesosphere, effectively separating a tracer‐enriched air mass in the north from air at lower latitudes. In the mesosphere, above the level of the vortex jet, a tracer‐depleted zone extends away from the north pole toward the equator and enrichment is confined to high northern latitudes. However, below this level, mixing processes cause tongues of gas to extend away from the polar region toward the equator. These features are not reproduced by current general circulation models and suggest that a residual polar circulation is present and that waves and instabilities form a more important part of Titan's atmospheric dynamics than previously thought. We also observe an unexpected enrichment of C4H2 in the northern stratosphere, which suggests photochemical polymerization of C2H2. Our observations provide stringent new constraints for dynamical and photochemical models and identify key polar processes for the first time. Some of the processes we see have analogues in Earth's polar vortex, while others are unique to Titan.
Development of a novel GLUT4 translocation assay for identifying potential novel therapeutic targets for insulin sensitization
Authors: Liu Franklin , Dallas-Yang Qing , Castriota Gino , Fischer Paul , Santini Francesca , Ferrer Marc , Li Jing , Akiyama Taro E. , Berger Joel P. , Zhang Bei B. , Jiang Guoqiang
Published: December 2008

GLUT4 (glucose transporter 4) plays important roles in glucose homoeostasis in vivo. GLUT4 expression and function are diminished in diabetic human and animal subjects. The goal of the present study is to develop a cell-based assay for identifying negative regulators of GLUT4 translocation as potential targets for the treatment of Type 2 diabetes. Traditional GLUT4 translocation assays performed in differentiated myocytes or adipocytes are difficult to perform, particularly in HTS (high-throughput screening) mode. In the present study, we stably co-expressed c-Myc and eGFP [enhanced GFP (green fluorescent protein)] dual-tagged recombinant GLUT4 with recombinant IRS1 (insulin receptor substrate 1) in HEK-293 cells (human embryonic kidney cells) (HEK-293.IRS1.GLUT4 cells). Insulin treatment stimulated both glucose uptake and GLUT4 translocation in these cells. GLUT4 translocation is quantified by a TRF (time-resolved fluorescence) assay in a 96-well HTS format. TRF assays confirmed insulin-stimulated GLUT4 translocation, which can be inhibited by PI3K (phosphoinositide 3-kinase) or Akt [also called PKB (protein kinase B)] inhibitors. Treatment with palmitate increased IRS1 serine phosphorylation and reduced insulin-stimulated Akt phosphorylation and GLUT4 translocation, indicating insulin resistance. Knockdown of PTEN (phosphatase and tensin homologue deleted on chromosome 10) and PTP1B (protein tyrosine phosphatase 1B) gene expression by siRNA (small interfering RNA) treatment significantly increased GLUT4 translocation only in cells treated with palmitate but not in untreated cells. Similar results were obtained on treatment with siRNA of JNK1 (c-Jun N-terminal kinase 1), S6K1 (ribosomal protein S6 kinase, 70 kDa, polypeptide 1) and PKCθ (protein kinase C θ). In summary, we have established and validated a novel GLUT4 translocation assay that is optimal for identifying negative regulators of GLUT4 translocation. In combination with more physiologically relevant secondary assays in myotubes and adipocytes, this assay system can be used to identify potential novel therapeutic targets for the treatment of Type 2 diabetes.
Structure of AsxTe100−x (20⩽x⩽60) glasses investigated with x-ray absorption fine structure, x-ray and neutron diffraction, and reverse Monte Carlo simulation
Authors: Jóvári P. , Yannopoulos S. N. , Kaban I. , Kalampounias A. , Lishchynskyy I. , Beuneu B. , Kostadinova O. , Welter E. , Schöps A.
Published: December 2008

A systematic and detailed investigation of the structure of AsxTe100−x glasses (20⩽x⩽60) has been undertaken using a combination of structure-probing techniques including high energy x-ray diffraction, neutron diffraction, and x-ray absorption fine structure measurements at the As and TeK edges. The experimental datasets were modeled simultaneously with the reverse Monte Carlo simulation technique. The results revealed that homonuclear bonding for both As and Te atoms is important over the whole glass concentration region studied. At the stoichiometric composition (As40Te60) the average As–As and Te–Te coordination numbers are as high as 1.7±0.2 and 1.3±0.1, respectively. The number of As–As and Te–Te bonds, as well as the average number of bonds/atom, evolves monotonically with composition. Arsenic atoms are threefold coordinated for all compositions investigated. It has also been shown that, in contrast to the results of previous studies, Te is predominantly twofold coordinated for x⩽50. Our results suggest that (i) chemical ordering does not play a decisive role in the formation of short-range order and (ii) similar to some other amorphous tellurides (e.g., Ge2Sb2Te5, GeSb2Te4, and As25Si40Te35) binary AsxTe100−x (x⩽50) alloys obey the “8−N” rule. A detailed comparison has been advanced between the structural details obtained from the present study and several physicochemical properties of As–Te. The comparison revealed striking similarities between the concentration dependence of structural and physicochemical properties.
Transparent and conductive electrodes based on unpatterned, thin metal films
Authors: O’Connor Brendan , Haughn Chelsea , An Kwang-Hyup , Pipe Kevin P. , Shtein Max
Published: December 2008

Transparent electrodes composed of ultrathin, unpatterned metal films are investigated in planar heterojunction (PHJ) and bulk heterojunction organic photovoltaic (OPV) cells. Optimal electrode composition and thickness are deduced from electrical and optical models and experiments, enabling a PHJ-OPV cell to be realized using a silver anode, achieving power conversion efficiency parity with an analogous cell that uses an indium tin oxide anode. Beneficial aspects of smooth, unpatterned metal films as transparent electrodes in OPV cells are also discussed in the text.
Effects of engineered Cu spacer on the interlayer coupling and giant magnetoresistance behavior in Pd/[Pd/Co]2/Cu/[Co/Pd]4 pseudo-spin-valves with perpendicular anisotropy
Authors: Thiyagarajah Naganivetha , Bae Seongtae
Published: December 2008

Effects of perpendicular interlayer coupling formed between two perpendicularly magnetized ferromagnetic multilayers separated by engineered Cu spacer on the giant magnetoresistance (GMR) behavior were investigated in the Pd (3 nm)/[Pd (1.2 nm)/Co (0.6 nm)]2/Cu (x nm)/[Co (0.3 nm)/Pd (0.6 nm)]4/Pd (3 nm) pseudo-spin-valves. It was clearly observed that an increase in Cu spacer thickness from 1.6 to 4.9 nm, decreased the perpendicular interlayer coupling field through the Cu spacer and correspondingly decreased the magnetoresistance ratio. It was found that this is due to the degradation of the perpendicular anisotropy caused by strain relaxation in the soft [Co/Pd] multilayers. Further experimental and theoretical analyses verified that the physical nature of the perpendicular interlayer coupling field is directly relevant to the topological and Ruderman–Kittel–Kasuya–Yosida (RKKY) type oscillatory coupling created in the [Co/Pd]2/Cu/[Co/Pd]4 multilayers. Unlike the spin valves with in-plane anisotropy, it was clearly verified that the contribution of topological coupling field to the perpendicular interlayer coupling field is negligibly small. In contrast, the oscillatory RKKY coupling field depending on the magnetization angle between the soft and hard [Co/Pd] multilayers dominantly determined the physical characteristics of perpendicular interlayer coupling field. Furthermore, even at a larger surface roughness of greater than 0.25 nm for tCu=6–16 nm, the slight oscillations in the GMR ratio corresponded well with the oscillations in the interlayer coupling field, although the GMR ratio showed an overall decreasing trend possibly due to shunting through the thicker Cu spacer. This indicates that the perpendicular interlayer coupling rather than the topological coupling is dominant in determining the GMR behavior. Based on the experimental and theoretical results, a physical model enabling the explanation of GMR behavior in [Co/Pd] based pseudo-spin-valves with perpendicular anisotropy is proposed: a perpendicular magnetostatic field, induced in between the soft and hard [Co/Pd] multilayers through Cu spacer by perpendicular anisotropy, is directly relevant to the perpendicular interlayer coupling field and dominantly controls the GMR characteristics. In addition, this model proposes that the GMR ratio is proportional to the sine of the angle between the soft and hard layer magnetizations from the perpendicular direction during magnetic reversal of the soft layer by an applied magnetic field. However this model is only applicable once the magnetization of the soft layer is slightly tilted away from the perpendicular direction by a critical angle (θC1=5–10°). Similar perpendicular interlayer coupling characteristics were also observed for the Cu spacers engineered by different input sputtering powers.
Electron carrier concentration dependent magnetization and transport properties in ZnO:Co diluted magnetic semiconductor thin films
Authors: Yang Z. , Biasini M. , Beyermann W. P. , Katz M. B. , Ezekoye O. K. , Pan X. Q. , Pu Y. , Shi J. , Zuo Z. , Liu J. L.
Published: December 2008

Diluted magnetic semiconducting ZnO:Co thin films with above room-temperature TC were prepared. Transmission electron microscopy and x-ray diffraction studies indicate the ZnO:Co thin films are free of secondary phases. The magnetization of the ZnO:Co thin films shows a free electron carrier concentration dependence, which increases dramatically when the free electron carrier concentration exceeds ∼1019 cm−3, indicating a carrier-mediated mechanism for ferromagnetism. The anomalous Hall effect is observed in the ZnO:Co thin films. The anomalous Hall coefficient and its dependence on longitudinal resistivity were analyzed. The presence of a side-jump contribution further supports an intrinsic origin for ferromagnetism in ZnO:Co thin films. These observations together with the magnetic anisotropy and magnetoresistance results support an intrinsic carrier-mediated mechanism for ferromagnetic exchange in ZnO:Co diluted magnetic semiconductor materials.
Biomicrofluidic lab-on-chip device for cancer cell detection
Authors: He J. H. , Reboud J. , Ji H. , Zhang L. , Long Y. , Lee C.
Published: December 2008

A lab-on-a-chip microfluidic device was designed, fabricated, and tested to be used in cancer cell or disease cell detection in body fluids. Mixtures of breast cancer cells MCF-7 and control cells MCF-10A were captured by meandering weir filters in microfluidic channels. A selective fluorescent complex 17β-estradiol-bovine serum albumin-fluorescein isothiocyanate enabled to specifically detect MCF-7 after only 4 min of contact. These signals are about seven times stronger than that of a labeling performed on conventional glass slides following the same protocol. The simple method could have the potential to replace complex existing cancer or disease detection schemes.
Two-dimensional image fusion of planar bone scintigraphy and radiographs in patients with clinical scaphoid fracture: An imaging study
Authors: Henriksen O. M. , Lonsdale M. N. , Jensen T. D. , Weikop K. L. , Holm O. , Duus B. , Friberg L.
Published: December 2008

Background: Although magnetic resonance imaging (MRI) is now considered the gold standard in second-line imaging of patients with suspected scaphoid fracture and negative radiographs, bone scintigraphy can be used in patients with pacemakers, metallic implants, or other contraindications to MRI. Bone scintigraphy is highly sensitive for the detection of fractures, but exact localization of scintigraphic lesions may be difficult and can negatively affect diagnostic accuracy.

Purpose: To investigate the influence of image fusion of planar bone scintigraphy and radiographs on image interpretation in patients with suspected scaphoid fracture.

Material and Methods: In 24 consecutive patients with suspected scaphoid fracture, a standard planar bone scintigraphy of both hands was supplemented with fusion imaging of the injured wrist. Standard and fusion images were evaluated independently by three experienced nuclear medicine physicians. In addition to the diagnosis, the degree of diagnostic confidence was scored in each case.

Results: The addition of fusion images changed the interpretation of each of the three observers in seven, four, and two cases, respectively, reducing the number of positive interpretations of two of the observers from 11 and nine cases to six and seven cases, respectively. The degree of diagnostic confidence increased significantly in two observers, and interobserver agreement increased in all three pairs of observers from 0.83, 0.57, and 0.73 to 0.89, 0.8, and 0.9, respectively.

Conclusion: Image fusion of planar bone scintigrams and radiographs has a significant influence on image interpretation and increases both diagnostic confidence and interobserver agreement.
Phosphorylation regulates targeting of cytoplasmic dynein to kinetochores during mitosis
Authors: Whyte Jacqueline , Bader Jason R. , Tauhata Sinji B.F. , Raycroft Maurice , Hornick Jessica , Pfister K. Kevin , Lane William S. , Chan Gordon K. , Hinchcliffe Edward H. , Vaughan Patricia S. , Vaughan Kevin T.
Published: December 2008

Cytoplasmic dynein functions at several sites during mitosis; however, the basis of targeting to each site remains unclear. Tandem mass spectrometry analysis of mitotic dynein revealed a phosphorylation site in the dynein intermediate chains (ICs) that mediates binding to kinetochores. IC phosphorylation directs binding to zw10 rather than dynactin, and this interaction is needed for kinetochore dynein localization. Phosphodynein associates with kinetochores from nuclear envelope breakdown to metaphase, but bioriented microtubule (MT) attachment and chromosome alignment induce IC dephosphorylation. IC dephosphorylation stimulates binding to dynactin and poleward streaming. MT depolymerization, release of kinetochore tension, and a PP1-γ mutant each inhibited IC dephosphorylation, leading to the retention of phosphodynein at kinetochores and reduced poleward streaming. The depletion of kinetochore dynactin by moderate levels of p50(dynamitin) expression disrupted the ability of dynein to remove checkpoint proteins by streaming at metaphase but not other aspects of kinetochore dynein activity. Together, these results suggest a new model for localization of kinetochore dynein and the contribution of kinetochore dynactin.
Regulation of EphB2 activation and cell repulsion by feedback control of the MAPK pathway
Authors: Poliakov Alexei , Cotrina Maria L. , Pasini Andrea , Wilkinson David G.
Published: December 2008

In this study, we investigated whether the ability of Eph receptor signaling to mediate cell repulsion is antagonized by fibroblast growth factor receptor (FGFR) activation that can promote cell invasion. We find that activation of FGFR1 in EphB2-expressing cells prevents segregation, repulsion, and collapse responses to ephrinB1 ligand. FGFR1 activation leads to increased phosphorylation of unstimulated EphB2, which we show is caused by down-regulation of the leukocyte common antigen–related tyrosine phosphatase receptor that dephosphorylates EphB2. In addition, FGFR1 signaling inhibits further phosphorylation of EphB2 upon stimulation with ephrinB1, and we show that this involves a requirement for the mitogen-activated protein kinase (MAPK) pathway. In the absence of activated FGFR1, EphB2 activates the MAPK pathway, which in turn promotes EphB2 activation in a positive feedback loop. However, after FGFR1 activation, the induction of Sprouty genes inhibits the MAPK pathway downstream of EphB2 and decreases cell repulsion and segregation. These findings reveal a novel feedback loop that promotes EphB2 activation and cell repulsion that is blocked by transcriptional targets of FGFR1.
Tight junctions potentiate the insulative properties of small CNS myelinated axons
Authors: Devaux Jerome , Gow Alexander
Published: December 2008

Claudin family proteins form the physical barriers of tight junctions (TJs) and regulate paracellular diffusion across polarized epithelia. In addition to these heterotypic TJs, claudin 11 forms autotypic TJs comprising the radial component of central nervous system myelin. The exact function of these TJs has been unclear, although their location at the membrane perimeter is well sited to regulate diffusion between the interstitium and intramyelinic space. In this study, we demonstrate that claudin 11 affords rapid nerve conduction principally for small diameter myelinated axons. Claudin 11–null mice have preserved myelin and axonal architecture, but as much as a 60% decrease in conduction. They also have increased action potential thresholds and activated internodal potassium channels. These data indicate that TJs modulate the biophysical properties of myelin. Computational modeling reveals that claudin 11 reduces current flow through myelin and moderates its capacitive charging. Together, our data shed new light on myelin structural components and our understanding of the biology and pathophysiology of this membrane.
Molecular architecture of inner dynein arms in situ in Chlamydomonas reinhardtii flagella
Authors: Bui Khanh Huy , Sakakibara Hitoshi , Movassagh Tandis , Oiwa Kazuhiro , Ishikawa Takashi
Published: December 2008

The inner dynein arm regulates axonemal bending motion in eukaryotes. We used cryo-electron tomography to reconstruct the three-dimensional structure of inner dynein arms from Chlamydomonas reinhardtii. All the eight different heavy chains were identified in one 96-nm periodic repeat, as expected from previous biochemical studies. Based on mutants, we identified the positions of the AAA rings and the N-terminal tails of all the eight heavy chains. The dynein f dimer is located close to the surface of the A-microtubule, whereas the other six heavy chain rings are roughly colinear at a larger distance to form three dyads. Each dyad consists of two heavy chains and has a corresponding radial spoke or a similar feature. In each of the six heavy chains (dynein a, b, c, d, e, and g), the N-terminal tail extends from the distal side of the ring. To interact with the B-microtubule through stalks, the inner-arm dyneins must have either different handedness or, more probably, the opposite orientation of the AAA rings compared with the outer-arm dyneins.
Collective cell migration requires vesicular trafficking for chemoattractant delivery at the trailing edge
Authors: Kriebel Paul W. , Barr Valarie A. , Rericha Erin C. , Zhang Guofeng , Parent Carole A.
Published: December 2008

Chemoattractant signaling induces the polarization and directed movement of cells secondary to the activation of multiple effector pathways. In addition, chemotactic signals can be amplified and relayed to proximal cells via the synthesis and secretion of additional chemoattractant. The mechanisms underlying such remarkable features remain ill defined. We show that the asymmetrical distribution of adenylyl cyclase (ACA) at the back of Dictyostelium discoideum cells, an essential determinant of their ability to migrate in a head-to-tail fashion, requires vesicular trafficking. This trafficking results in a local accumulation of ACA-containing intracellular vesicles and involves intact actin, microtubule networks, and de novo protein synthesis. We also show that migrating cells leave behind ACA-containing vesicles, likely secreted as multivesicular bodies and presumably involved in the formation of head-to-tail arrays of migrating cells. We propose that similar compartmentalization and shedding mechanisms exist in mammalian cells during embryogenesis, wound healing, neuron growth, and metastasis.