bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis, Characterization of Copper‐Loaded Carboxymethyl‐Chitosan Nanoparticles with Effective Antibacterial Activity
Authors: Gu Chunju , Sun Bin , Wu Wenhua , Wang Fengchuan , Zhu Meifang
Published: August 2007

Summary: Copper‐loaded carboxymethyl‐chitosan (CMCS‐Cu) nanoparticles were successfully prepared by chelation under aqueous conditions. The effect of degree of deacetylation and substitution, the molecular weight of CMCS, CMCS concentration, Cu(II) ions concentration, pH value of the solution, as well as temperature, on the morphology of the yielded particles were systematically investigated. The physicochemical properties of the particles were determined by size and zeta potential analysis, FTIR analysis, DLS, TEM, SEM and XRD pattern. FTIR and XRD revealed that Cu (II) ions and CMCS formed a chelate complex. The size of CMCS‐Cu particles shows a good consistency by DLS, TEM, and SEM. The nanoparticles with the size of about 70 nm have been prepared at 0.13 wt% CMCS, 16 mmol/L Cu(II) ions, pH value 4.56 at 25 °C. The antibacterial activity of CMCS, CMCS‐Cu normal particles with the size of about 1000 nm and CMCS‐Cu nanoparticles with the size of less than 100 nm against Staphylococcus aureus was evaluated by vibration method. Results show that the antibacterial efficiency of nanoparticles reached 99%, which is much more efficient than 68.9% of the normal one and 6.1% of CMCS. CMCS‐Cu nanoparticles were proved to be a good novel antibacterial material.
Functional Opals from Reactive Polymers: Complex Structures, Sensors, and Modified Photoluminescence
Authors: Fleischhaker Friederike , Lange Birger , Zentel Rudolf
Published: August 2007

Summary: This paper describes the synthesis and properties of functional opal structures, so‐called colloidal photonic crystals (CPCs), from a variety of reactive polymers. Photoprocessable opals are presented as well as opals with incorporated “smart” defect layers that can be actively addressed by external stimuli. In addition, opals with functional bio‐macromolecular defects have been developed. They present a new class of materials for optical biomonitoring through shifts of the induced photonic defect mode. Strong modification of photoluminescence according to the photonic bandstructure is observed from opals with embedded exclusively luminescent defect layer.
Formation of Hollow Polymeric Microspheres with Functionalized Surface on the Basis of Latex Particles with Multilayered Structure
Authors: Shevchuk Oleh , Tokarev Viktor , Bukartyk Natalya , Voronov Stanislav
Published: August 2007

Summary: Latices with “core‐shell” particle morphology containing polar “core” and a shell on the basis of copolymer of styrene and functional vinyl monomer (allyl alcohol, vinyl acetate, methacrylic acid) has been obtained as a result of graft‐copolymerization initiated from the surface of (meth)acrylate latex particles previously modified with functional polyperoxides. The processes of functional shell grafting as well as the processes of latex particle swelling with obtaining hollow microspheres due to neutralization of core carboxylic groups have been studied.
Temperature and pH‐Sensitive Polymers with Hydrophobic Spacers for the Controlled Delivery of Drugs
Authors: Licea‐Claveríe Angel , Cornejo‐Bravo José Manuel , Salgado‐Rodríguez Rodolfo , Santos‐Rosas Dolores del Rosario , Lugo‐Medina Eder , Ramos‐Ibarra Marco Antonio , Arndt Karl‐Friedrich
Published: August 2007

Summary: Acid methacrylates containing hydrophobic aliphatic and aromatic spacers were used to prepare pH‐sensitive ampholytic hydrogels and bidimensional temperature‐ (T) and pH‐sensitive hydrogels. Their swelling behaviour was studied by changing the pH and temperature of buffer solutions. Salicylamide, salicylic acid and green fluorescent protein (GFP) as model drugs were loaded into the gels and their release kinetics studied under simulated gastric and intestinal conditions. T‐ and pH‐sensitive hydrogels containing aliphatic spacers show sustained release of analgesics depending on pH (e.g. 7.4); while longer aliphatic spacers resulted in drug release depending on pH and temperature (T < transition T). GFP was released from temperature‐ and pH‐sensitive ampholytic hydrogels after different lag times depending on hydrogel composition.
Application of Polyelectrolytic Temperature‐Responsive Hydrogels in Chemical Sensors
Authors: Guenther Margarita , Gerlach Gerald , Corten Cathrin , Kuckling Dirk , Muller Martin , Shi Zhangman , Sorber Joerg , Arndt Karl‐Friedrich
Published: August 2007

Summary: A rapidly expanding field of on‐line process monitoring and on‐line control in biotechnology, food industry, pharmaceutical industry, process chemistry, environmental measuring technology, water treatment and sewage processing requires the development of new micro fabricated reliable chemical and biosensors that are specific for particular species and can attain the analytic information in a faster, simpler and cheaper manner. Using a functionalised polymer coating in sensors provides the possibility to detect, transmit and record the information regarding the concentration change or the presence of a specific analyte (a chemical or biological substance that needs to be measured) by producing a signal proportional to the concentration of the target analyte. However, the sensor response time and signal reproducibility are limited by the visco‐elastical and hysteresis behaviour of the polymer material. We propose some methods improving the properties of the chemical sensors on the basis of thermo‐shrinking N‐isopropylacrylamide (NIPAAm) copolymer gels.
Controlled Thermosensitivity of the Poly(N‐isopropyl‐ acrylamide‐co‐N,N′‐dimethyl(methacryloyloxyethyl)‐ ammonium propane sulfonate) Hydrogels
Authors: Kamenova Irena , Kuckling Dirk , Georgiev George , Adler Hans‐Jurgen P.
Published: August 2007

Summary: The N‐isopropylacrylamide (NIPAM) and N,N′‐dimethyl‐(methacryloyloxyethyl) ammonium propane sulfonate (DMAPS) copolymer networks having monomer units with an opposite thermoassembling ability are synthesized and analyzed. The network composition is of crucial importance for their degree of swelling (Q) and Q‐Temperature (T) dependences. After the Q normalization these dependences outline two classes of networks which hydrogels expel or imbibe water with T. The boundary network (with 0.39 mole fraction of DMAPS monomer units) defines a critical T (Tcr) at which Q is the same as that at the initial T (To), but with a structure organization, different than that at To. The hydrogels thermoreversibility at the stepped T change, and the salt effect on the Q‐T dependences are demonstrated also.
Mechanical Properties and Phase Transition of High Clay Content Clay/Poly(N‐isopropylacrylamide) Nanocomposite Hydrogel
Authors: Liu Yang , Zhu Meifang , Liu Xiaoli , Jiang Y.M. , Ma Y. , Qin Z.Y. , Kuckling Dirk , Adler Hans‐Jurgen P.
Published: August 2007

Summary: A series of high clay content Clay‐S/PNIPAAm nanocomposite hydrogels (S‐N gels) has been successfully prepared by in situ polymerization. Their mechanical properties and phase transition behavior has been systematically investigated. It was found that S‐N gels show high tensile strength, high elongation at break, fast stress relaxation, high hysteresis, and poor resilience, which may be ascribed to the hydrophilicity and flexibility of PNIPAAm chains. It was also concluded that the macroscopic phase transition behavior of S‐N gels depend on the ratio of Segments II (thermosensitive segments) to Segments I (non‐thermosensitive segments).
Temperature Sensitive Hydrogels Based on Hydroxypropylcellulose by High Energy Irradiation
Authors: Gottlieb Ronny , Kaiser Claudia , Gohs Uwe , Arndt Karl‐Friedrich
Published: August 2007

Summary: Stimuli sensitive hydrogels change their properties in dependence on a liquid environment. The temperature sensitive hydroxypropylcellulose (HPC) gel shows a volume phase transition in water at about 48 °C. For different applications a crosslinking of a preformed layer of the dry polymer on a support is necessary. It is known, that HPC dissolved in water is crosslinkable by high energy irradiation (electron beam). Now, we could show, that HPC can be crosslinked in the dry state by high energy irradiation. This allows the preparation of thin crosslinked layers of HPC on silicone substrates.
Elongational Viscosity and Foaming Behavior of PP Modified by Electron Irradiation or Nanotube Addition
Authors: Pötschke Petra , Krause Beate , Stange Jens , Munstedt Helmut
Published: August 2007

Summary: In this study, two different routes were chosen which are expected to influence the elongational viscosity and, thus, the foaming behavior of polypropylene (PP). Electron irradiation of a linear PP was performed at room temperature using different doses. Enhanced long‐chain branching was observed with increased irradiation dose. In addition, a linear PP was filled with 5 wt% multiwalled carbon nanotubes (MWNT) by melt mixing at 200 °C. These modified PP materials were investigated with respect to their shear and elongational behavior. After foaming, irradiated PP led to an expansion factor which is about 60% higher than that of the non‐irradiated product. In case of PP filled with 5 wt% MWNT the value of the expansion factor is about 70% higher than that of pure PP expanded under the same conditions. The cell structure is much finer in both cases as compared to unmodified PP.
Polyurethane‐Based Extended Release Form of Piroxicam
Authors: Grigorieva Maya , Zakashun Tetyana , Galatenko Natalia
Published: August 2007

Summary: The anti‐inflammatory effect of piroxicam (Px) immobilized on a polyurethane (PU) matrix was studied in vivo by measuring levels of t‐methylimidazole acetic acid (t‐MeImAA) in urine of experimental animals. Released into body from the polymeric matrix, Px affected inflammation process, significantly reducing the t‐MeImAA levels. The retention of Px within the PU/drug system – largely due to physical modification of the polymer – resulted in durable therapeutic action of the system.
Geometric T–Ω approach to solve eddy currents coupled to electric circuits
Authors: Specogna Ruben , Suuriniemi Saku , Trevisan Francesco
Published: August 2007

This paper describes a systematic geometric approach to solve magneto‐quasi‐static coupled field–circuit problems. The field problem analysis is based on formulating the boundary value problem with an electric vector potential and a scalar magnetic potential. The field–circuit coupling and the definition of potentials are formally examined within the framework of homology theory. Copyright © 2007 John Wiley & Sons, Ltd.
Human rights and development: the case of local government transformation in South Africa
Authors: van Rensburg Linda Jansen , Naudé Wim
Published: August 2007

Local governments throughout the world are assuming a more important role in economic development of their communities as an increasing number of governments begin to decentralise powers and functions. As these lower levels of government seek sustainable local economic development (LED) strategies the human rights approach towards development becomes pertinent as globalisation accelerates. This article proposes an emphasis on socio‐economic rights as the basis for sustainable LED in developing countries. The article is based on the experience of South African local government in the period after 1994, leading up to the first democratic local government elections on 5 December 2000. Proceeding from the view that the promotion of human rights is necessary for the promotion of economic development, the article critically assesses the role of local government in the promotion of LED through a rights‐based approach. It is argued that the identification in the South African Constitution of local government with basic service provision (recently emphasised by a Constitutional court judgement) will place socio‐economic rights at the centre of LED strategies in South Africa. It is argued that this is indeed the most appropriate cornerstone of LED in South Africa. However, the transformation process that leads the country towards its progressive Constitution needs to be maintained and this article identifies five broad areas for transformation that may still be needed to entrench an adequate human rights culture within the sphere of local governance. Copyright © 2007 John Wiley & Sons, Ltd.
Quantitative proteomic approaches for biomarker discovery
Authors: Hu Zhiyuan , Hood Leroy , Tian Qiang
Published: August 2007

The rapid advances in proteomic technologies have made possible systematic analysis of hundreds to thousands of proteins in clinical samples with the promise of uncovering novel protein biomarkers for various disease conditions. We will discuss in this review article current MS and protein chip‐based quantitative proteomic approaches and their application in biomarker discovery. The emphasis will be placed on new quantification strategies employing stable isotopic labeling coupled with MS/MS, and antibody‐based protein chips and nanodevices. The strength and weakness of each technology are briefly highlighted.
Clinical application of tear proteomics: Present and future prospects
Authors: Wu Kaili , Zhang Yanli
Published: August 2007

Human tear fluid is charactered with very small volume and complex protein constitutes with a very large orders of magnitude. The tear proteome analysis provides a unique dataset (i.e., specific protein markers or protein patterns) that may be correlated to more effective diagnosis, prognosis, and response to therapy. Compared to less than 100 tear proteins obtained by the traditional methods, more than 400 proteins have been found in human tear fluid by current proteomic technologies. Many proteomics techniques, such as 2‐DE, MALDI‐TOF‐MS, LC‐MS, SELDI‐TOF‐MS, protein arrays, have been used to perform tear proteome analysis in healthy and/or disease subjects. The clinical application of tear proteomics needs suitable tear collection methods, standard tear handling procedures, and more sensitive and reliable proteomic technologies.
Unconditionally stable perfectly matched layer boundary conditions
Authors: De Raedt H. , Michielsen K.
Published: August 2007

A brief review is given of a systematic, product‐formula based approach to construct unconditionally stable algorithms for solving the time‐dependent Maxwell equations. The fundamental difficulties that arise when we want to incorporate uniaxial perfectly matched layer boundary conditions into this scheme is discussed. We construct an algorithm that circumvents these difficulties and is unconditionally stable. Results of simulations for a point source and a plane current source inside a three‐dimensional volume illustrate that in practice, the algorithm performs as theoretically expected. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Erratum: Predicting the morphological and hydraulic consequences of river rehabilitation
Authors: Schweizer S. , Borsuk M. E. , Reichert P.
Published: August 2007

Erratum: Predicting the Morphological and Hydraulic Consequences of River Rehabilitation. S. Schweizer, M. E. Borsuk and P. Reichert. River Research and Applications (23)3: 303–322.

Equation 17 on page 313 should read $r={{e \cdot \theta ^{\,0.5}} \over {\left( {{{d_{10} } \over {d_m }}} \right)^{3.5} \cdot {\mathop{\rm Re}\nolimits} _f {\hskip -.1pt} ^{1.5} \cdot i^{\,0.67} }}$ and not $r={{e \cdot \theta ^{\,0.5} } \over {\left( {{{d_{10} } \over {d_m }}} \right)3.5 \cdot {\mathop{\rm Re}\nolimits} _f ^{15} \cdot i^{\,0.67} }}$ as published.
Impact of weirs on fish communities in a piedmont stream
Authors: Poulet N.
Published: August 2007

The impact of large dams on fish communities is much better documented than that of weirs. This paper investigates the influence of weirs on fish community patterns along a piedmont river (the River Viaur). Presence/absence of species was obtained distant from a weir (NW), and immediately downstream (DW) and immediately upstream (UW) of the weir. More than half of the species captured were non‐native, probably introduced when upstream reservoirs were built. Most of these species were eurytopic or limnophilic. Species richness at UW sites and the number of introduced species found at each site did not depend on the distance from the source (DFS). UW sites had more introduced and limnophilic species than NW sites. Conversely, NW had more rheophilic species than UW. Furthermore, total species richness (SRT) was higher at DW than NW suggesting a direct influence of the weir on the downstream community. UW sites were characterized by the presence of tench, roach and bleak which were scarce in NW sites where brown trout predominated. Weirs appear to modify habitat to favour the colonization of introduced species, and therefore have influenced the structure of fish communities. The study underlines the importance of local conditions in artificially‐influenced rivers. Copyright © 2007 John Wiley & Sons, Ltd.
Variables related to stress‐related growth among Turkish breast cancer patients
Authors: Karanci Ayşe Nuray , Erkam Asli
Published: August 2007

The present study aimed to examine the validation of the use of the stress‐related growth scale and the variables related to stress‐related growth among Turkish breast cancer patients. Participants were 90 breast cancer patients. Consistent with the literature, results revealed that both social support and problem‐solving coping strategies related to higher levels of stress‐related growth. Furthermore, income level of the participants and depression scores were also found to be associated with stress‐related growth. From these variables, social support and problem‐solving coping were found to be positively associated with stress‐related growth whereas income level and depression scores were found to be negatively associated with stress‐related growth. These findings were discussed in the light of relevant literature. Copyright © 2007 John Wiley & Sons, Ltd.
Starch Functionalized by Chloroacetate Groups: Coupling of Bioactive Salicylic Acid
Authors: Jantas Roman , Draczyński Zbigniew , Stawski Dawid
Published: August 2007

Starch partially functionalized with chloroacetate groups was obtained by reaction of starch with chloroacetyl chloride using the N,N‐dimethylacetamide/5%lithium chloride system as solvent and pyridine as catalyst. The coupling of salicylic acid to starch functionalized with chloroacetate groups was carried out by reaction with the sodium salt of salicylic acid. The structures of chloroacetylated starch and starch‐salicylic acid adducts were determined by means of FTIR, 1H‐NMR and 13C‐NMR spectra. The degree of substitution per anhydroglucose unit (AGU) of chloroacetylated starch was calculated from the chloride content and ranged from 0.52 to 2.34, depending on the ratio of chloroacetyl chloride to starch. The hydrolysis of starch‐salicylic acid adducts in a heterogeneous phase showed that the release of sodium salicylate from tablets is dependent on the hydrophilic character of the adduct and on the pH value of the medium.
Placental vascularization measured by three‐dimensional power Doppler ultrasound at 11 to 13 + 6 weeks' gestation in normal and aneuploid fetuses
Authors: Rizzo G. , Capponi A. , Cavicchioni O. , Vendola M. , Arduini D.
Published: August 2007

Objective

To establish the potential role of three‐dimensional (3D) power Doppler evaluation of the placental circulation in aneuploidy screening at 11 to 13 + 6 weeks of gestation.

Methods

3D power Doppler ultrasound examination of the placenta was performed in 25 pregnancies with fetuses with abnormal karyotype and in 100 control pregnancies at 11 to 13 + 6 weeks of gestation. Using the same pre‐established settings for all cases, the vascularization index (VI), flow index (FI) and vascularization flow index (VFI) were calculated for the whole placenta.

Results

In the chromosomally normal group all the vascular indices increased significantly with advancing gestation between 11 and 13 + 6 weeks (VI: r = 0.482, P < 0.001; FI: r = 0.295, P = 0.0029; VFI, r = 0.484, P < 0.001). In the chromosomally abnormal group, the flow indices were not significantly different from normal in cases with trisomy 21 (13 cases), but they were significantly reduced compared with normal in cases with trisomies 13 and 18 (VI: t = 8.321, P < 0.0001: FI: t = 12.934, P < 0.0001; VFI: t = 7.608, P < 0.0001).

Conclusions

3D power Doppler evaluation of the placental circulation is not useful in screening for trisomy 21, and unlikely to further increase the already high detection rate for trisomies 13 and 18. However, we provide normal ranges of placental vascular indices between 11 + 0 and 13 + 6 weeks of gestation, which may be useful in future research on placental vascularity in certain at‐risk pregnancies. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.
Congenital adrenal hyperplasia: Diagnostic advances
Authors: Torresani T. , Biason‐Lauber Anna
Published: August 2007

Congenital adrenal hyperplasia is a group of autosomal recessive disorders resulting from the deficiency of one of the five enzymes required for the synthesis of cortisol in the adrenal cortex. The most frequent is steroid 21‐hydroxylase deficiency, accounting for more than 90% of cases. Much has been learned about the genetics of the various clinical forms of 21‐hydroxylase deficiency, and correlations between the genotype and the phenotype have been studied extensively. Gene‐specific diagnosis is now feasible and neonatal screening and prenatal treatment have been widely implemented. This discussion will be limited to the most common form of congenital adrenal hyperplasia, with focus on the diagnostic advances in this disease.
Rapid Preparation of Fluorescent 9‐Anthrylmethyl Esters for Fatty Acid Analysis of Small Amount of Triacylglycerols
Authors: Ando Yasuhiro , Haba Yusuke , Soma Kazutaka , Hiraoka Yuko , Takatsu Tetsuya
Published: August 2007

This paper proposes a one‐step method for preparation of fluorescent 9‐anthrylmethyl esters from triacylglycerols (TAG) ranging in amount from 0.1 to 5 μg. It involves base‐catalyzed transesterification using potassium 9‐anthracenemethoxide, prepared by proton exchange between 9‐anthracenemethanol and potassium tert‐butoxide. Transesterification for 10 min at room temperature gave the fatty acid 9‐anthrylmethyl esters in nearly maximal yields (82–85%). The products could be analyzed by reversed‐phase HPLC without purification. Excellent linear relationships were observed for standard curves of 10–250 pmol of TAG standards (16:0, 19:0, 18:2 and 22:6), and differences in the slopes were less than 5% among the standards. Almost consistent compositions of the esters were observed for the products formed from 0.5 to 5 μg or less of fish oils TAG, and they were similar to those obtained by HPLC of ordinary multi‐step synthesis products and by GLC of methyl esters. The present method is a great improvement of derivatization time, and is powerful for fatty acid analysis of small amounts of natural TAG.
THE MULTIPLE SUBSET COUPON COLLECTING PROBLEM
Authors: Chang Kuang-Chao , Ross Sheldon M.
Published: August 2007

Suppose that there are n types of coupons and that each new coupon collected is type i with probability pi. Suppose, further, that there are m subsets of coupon types and that coupons are collected until all of the types of at least one of these subsets have been collected. When these subsets have no overlap, we derive expressions for the mean and variance of the number of coupons that are needed. In the general case where the subsets can overlap, we derive the mean of the number that are needed. We also note that this number is an increasing failure rate on average random variable and we present a conjecture as to a sufficient condition for it to be an increasing failure rate random variable.
On photolytic synthesis of sulphur-bearing organic molecules by reacting S or S2 with the hydrogen end-capped polyyne C10H2
Authors: Heymann Dieter
Published: August 2007

The photolysis of dilute solutions of octacyclosulphur or hexacyclosulphur in n-hexane with 253.6 nm UV radiation produces S and possibly S2. The ‘ring-opening’ yields of these sulphur molecules range from 0.2 to 0.7. When the hydrogen end-capped polyyne C10H2 is irradiated in n-hexane, it transforms into unidentified products with a quantum yield of 3×10−5. When octacyclosulphur is added to the solution, the yield rises to 7×10−3. The putative sulphur-bearing product(s) could not be identified. It is suggested that sulphur-bearing molecules might be formed in astronomical settings by reactions of carbon molecules having triple or double C—C bonds with photolytically produced S and/or S2.
Grouping dynamics of suspended matter in tidal channels
Authors: Winter Christian , Katoshevski David , Bartholomä Alexander , Flemming Burg W.
Published: August 2007

Small‐scale suspended sediment dynamics involve transport modes where grouping of suspended particulate matter (SPM) forms distinct patterns in the water. Field data on suspended matter dynamics at a particular location of a tidal channel show the frequent occurrence of turbidity clouds. These appear at spatial scales of tens of meters and temporal orders of minutes. In situ grain‐size analysis reveals that the turbidity clouds are mainly composed of aggregates around 0.35 mm in size. Although the SPM signal reveals similar oscillations as the transporting current, no direct correlation was observed between the occurrence of clouds and local hydrodynamic characteristics. To test how the formation of turbidity clouds can be related to the hydrodynamic environment and particle motion, we developed a numerical model for the simulation of particle grouping. The simulations show stable and weakly stable modes of particle clustering, depending on the environmental conditions. A prominent dependence of group stability on the amplitude of current velocity oscillations is revealed. As the local dynamics can be considered to be near the derived threshold of stable and weakly stable grouping, the temporal occurrence of turbidity clouds is explained by the temporal exceedance of a critical oscillation amplitude and the availability of suspended matter as the main limiting factors.
Marked seasonality in the concentrations and sea‐to‐air flux of volatile iodocarbon compounds in the western English Channel
Authors: Archer Stephen D. , Goldson Laura E. , Liddicoat Malcolm I. , Cummings Denise G. , Nightingale Philip D.
Published: August 2007

In the first seasonal study of volatile iodinated organic compounds (VICs) in the open sea, concentrations of five VICs were measured approximately weekly at four depths, over 20 months from July 2002 to April 2004, in the western English Channel. Seawater concentrations varied seasonally by an order of magnitude for all five compounds, with winter minima and, generally, late summer/autumn maxima. The average contribution to the dissolved VIC pool was chloroiodomethane (39%), diiodomethane (33%), iodomethane (22%), iodoethane (6%), and bromoiodomethane (4%). Total sea‐to‐air flux of iodine atoms carried by the VICs (15.5 μmol I m−2 yr−1) was approximately fourfold higher than that for iodomethane alone. This contrasts with previous studies that indicated that iodomethane was the main vector of iodine away from macroalgal beds. The estimated sea‐to‐air flux takes into account the significant airside control of the gas exchange of certain VICs, particularly diiodomethane; for which a 30% reduction in average daily flux was observed when an additional airside transfer velocity was included in the calculations. Because of their high reactivity, chloroiodomethane and diiodomethane are likely to drive the atmospheric organic iodine chemistry over these shelf seas, rather than the monohalogenated VICs.
A study of the number of sand grains lifting off per unit time and per unit sand bed area
Authors: Hong Cheng , Xue‐Yong Zou , Chun‐Lai Zhang
Published: August 2007

Aeolian sand flow is an especial two‐phase flow of gas and solid resulted from sands carried by wind to cause the spatial displacement. To simplify this complex process, researchers have divided it into four interacting subprocesses: jumping of sand grains, movement of sand grains in the airflow, changes of the airflow due to the moving sand grains, and impacts between falling sand grains and sand grains in the underlying sand bed. Although it simplifies Aeolian sand flow enough to permit the development of models of these subprocesses, no theory of Aeolian sand flow will be complete without a consideration of coupling among the subprocesses. In addition, two key physical variables must be defined: the probability density distribution for the initial liftoff velocities of saltating sand grains and the number of sand grains lifting off per unit time and per unit sand bed area (also called liftoff rates). Little data exist on liftoff rates because of the difficulty of direct measurements and theoretical analysis. This paper combines wind tunnel experimental data with a theoretical analysis to provide a preliminary solution based on the probability density distribution for the initial liftoff velocities of sand grains. The result shows that liftoff rates increase rapidly with increasing of friction wind velocities. The relationship between friction wind velocities and liftoff rates can be expressed as: N = A12 + 2A1B1u* + B12u*2, A1 = −9858.87, B1 = 14,830.07, R2 = 0. 97. Although the results of this study require additional experimental validation, they provide a strong basis for future research.
Spatial and temporal patterns of nitrogen deposition in China: Synthesis of observational data
Authors: Lü Chaoqun , Tian Hanqin
Published: August 2007

Anthropogenic nitrous pollutant emissions in China significantly increased during the last decades, which contributed to the accelerated nitrogen (N) deposition. In order to characterize spatial pattern of nitrogen deposition, we employed the kriging technique to interpolate sampling data of precipitation chemistry and ambient air concentration from site‐network observations over China. The estimation of wet deposition in China was limited to aqueous NO3− and NH4+, while ambient NO2 was the only species involved in the predicted dry deposition fluxes. To obtain wet deposition fluxes, precipitation concentration was multiplied by 20‐year mean precipitation amounts with a resolution of 10 × 10 km. Dry deposition fluxes were products of the interpolated ambient NO2 concentration and deposition velocities modeled for the main vegetation types in China. The total deposition rates of wet and dry deposition peaked over the central south China, with maximum values of 63.53 kg N ha−1 yr−1, and an average value of 12.89 kg N ha−1 yr−1. With ambient NO2 concentration data spanning from the year 1990 through 2003, we detected and evaluated trends in the time series of the annual values of atmospheric NO2 concentration. Significant upward trends at 21 of 102 sites were exhibited, with median percent change of 61.45% over the period 1990–2003. In addition, spatially continuous patterns of dry deposition fluxes based on ambient NO2 measurements in two 5‐year phases, 9 years apart, were carried out. On average, there was a rise of 7.66% in NO2 dry deposition during 9 years throughout China.
Hydraulic modeling of runoff over a rough surface under partial inundation
Authors: Roche N. , Daïan J.‐F. , Lawrence D. S. L.
Published: August 2007

This study presents a numerical method to derive the Darcy‐Weisbach friction coefficient for overland flow under partial inundation of surface roughness. To better account for the variable influence of roughness with varying levels of emergence, we model the flow over a network which evolves as the free surface rises. This network is constructed using a height numerical map, based on surface roughness data, and a discrete geometry skeletonization algorithm. By applying a hydraulic model to the flows through this network, local heads, velocities, and Froude and Reynolds numbers over the surface can be estimated. These quantities enable us to analyze the flow and ultimately to derive a bulk friction factor for flow over the entire surface which takes into account local variations in flow quantities. Results demonstrate that although the flow is laminar, head losses are chiefly inertial because of local flow disturbances. The results also emphasize that for conditions of partial inundation, flow resistance varies nonmonotonically but does generally increase with progressive roughness inundation.
Aerosol and fresh snow chemistry in the East Rongbuk Glacier on the northern slope of Mt. Qomolangma (Everest)
Authors: Ming Jing , Zhang Dongqi , Kang Shichang , Tian Wanshun
Published: August 2007

An intensive and simultaneous sampling for aerosol and fresh snow was conducted at Repula Col of the East Rongbuk Glacier near Mt. Qomolangma during the late Indian summer monsoon season in 2003. Aerosol and snow chemistry (including the species of Na+, K+, Mg2+, Ca2+, Cl−, SO42−, and NO3−) is analyzed and discussed. Anions account for a majority of the air quality, and SO42− is the most loaded species. Local emission by land weathering does not contribute significantly to the loading of Mg2+ and Ca2+, and their high concentration is related to their continental desert sources. The meridional dynamic force of Indian monsoon is efficient to the loading of Na+, and Na+/Ca2+ could be used to distinguish air masses of maritime or continental which dominate the air quality. The signal of crustal SO42− from Central/West Asia or farther Africa is weak, and mixed sources (anthropogenic and crustal) of SO42− dominate its loading in aerosol samples. Air–snow scavenging ratios of these species are calculated and compared with the other results in some previous studies. The scavenging ratio of SO42− as the most heavily loaded species is around 200, which is comparable with that in Greenland.
Contact instability of thin elastic films on patterned substrates
Authors: Mukherjee Rabibrata , Pangule Ravindra C. , Sharma Ashutosh , Banerjee Indrani
Published: August 2007

The free surface of a soft elastic film becomes unstable and forms an isotropic labyrinth pattern when a rigid flat plate is brought into adhesive contact with the film. These patterns have a characteristic wavelength, λ∼3H, where H is the film thickness. We show that these random structures can be ordered, modulated, and aligned by depositing the elastic film (cross-linked polydimethylsiloxane) on a patterned substrate and by bringing the free surface of the film in increasing adhesive contact with a flat stamp. Interestingly, the influence of the substrate “bleeds” through the film to its free surface. It becomes possible to generate complex two-dimensional ordered structures such as an array of femtoliter beakers even by using a simple one-dimensional stripe patterned substrate when the instability wavelength, λ∼3H, nearly matches the substrate pattern periodicity. The free surface morphology is modulated in situ by merely varying the stamp-surface separation distance. The free surface structures originating from the elastic contact instability can also be made permanent by the UV-ozone induced oxidation and stiffening.
Tuning electronic eigenvalues of benzene via doping
Authors: Marcon Valentina , von Lilienfeld O. Anatole , Andrienko Denis
Published: August 2007

Using variable atomic numbers within molecular grand-canonical ensemble theory, the highest occupied Kohn-Sham eigenvalue of isoelectronic benzene derivatives is tuned. The performed transmutational changes correspond to the iterative doping with boron and nitrogen. The molecular Fukui function proves to be a reliable index in order to predict the changes in the highest occupied molecular orbital eigenvalue due to doping.
Annealed importance sampling of peptides
Authors: Lyman Edward , Zuckerman Daniel M.
Published: August 2007

Annealed importance sampling assigns equilibrium weights to a nonequilibrium sample that was generated by a simulated annealing protocol [R. M. Neal, Stat. Comput. 11, 125 (2001)]. The weights may then be used to calculate equilibrium averages, and also serve as an “adiabatic signature” of the chosen cooling schedule. In this paper we demonstrate the method on the 50-atom dileucine peptide and an alanine 5-mer, showing that equilibrium distributions are attained for manageable cooling schedules. For dileucine, as naively implemented here, the method is modestly more efficient than constant temperature simulation. The alanine application demonstrates the success of the method when there is little overlap between the high (unfolded) and low (folded) temperature distributions. The method is worth considering whenever any simulated heating or cooling is performed (as is often done at the beginning of a simulation project or during a NMR structure calculation), as it is simple to implement and requires minimal additional computational expense. Furthermore, the naive implementation presented here can be improved.
Basis set convergence of post-CCSD contributions to molecular atomization energies
Authors: Karton Amir , Taylor Peter R. , Martin Jan M. L.
Published: August 2007

Basis set convergence of correlation effects on molecular atomization energies beyond the coupled cluster with singles and doubles (CCSD) approximation has been studied near the one-particle basis set limit. Quasiperturbative connected triple excitations, (T), converge more rapidly than L−3 (where L is the highest angular momentum represented in the basis set), while higher-order connected triples, T3−(T), converge more slowly—empirically, ∝L−5∕2. Quasiperturbative connected quadruple excitations, (Q), converge smoothly as ∝L−3 starting with the cc-pVTZ basis set, while the cc-pVDZ basis set causes overshooting of the contribution in highly polar systems. Higher-order connected quadruples display only weak, but somewhat erratic, basis set dependence. Connected quintuple excitations converge very rapidly with the basis set, to the point where even an unpolarized double-zeta basis set yields useful numbers. In cases where fully iterative coupled cluster up to connected quintuples (CCSDTQ5) calculations are not an option, CCSDTQ(5) (i.e., coupled cluster up to connected quadruples plus a quasiperturbative connected quintuples correction) cannot be relied upon in the presence of significant nondynamical correlation, whereas CCSDTQ(5)Λ represents a viable alternative. Connected quadruples corrections to the core-valence contribution are thermochemically significant in some systems. We propose an additional variant of W4 theory [A. Karton et al., J. Chem. Phys. 125, 144108 (2006)], denoted W4.4 theory, which is shown to yield a rms deviation from experimental atomization energies (active thermochemical tables, ATcT) of only 0.05kcal∕mol for systems for which ATcT values are available. We conclude that “3σ⩽1kJ∕mol” thermochemistry is feasible with current technology, but that the more ambitious goal of ±10cm−1 accuracy is illusory, at least for atomization energies.
Tip-sample distance control using photothermal actuation of a small cantilever for high-speed atomic force microscopy
Authors: Yamashita Hayato , Kodera Noriyuki , Miyagi Atsushi , Uchihashi Takayuki , Yamamoto Daisuke , Ando Toshio
Published: August 2007

We have applied photothermal bending of a cantilever induced by an intensity-modulated infrared laser to control the tip-surface distance in atomic force microscopy. The slow response of the photothermal expansion effect is eliminated by inverse transfer function compensation. By regulating the laser power and regulating the cantilever deflection, the tip-sample distance is controlled; this enables much faster imaging than that in the conventional piezoactuator-based z scanners because of the considerably higher resonant frequency of small cantilevers. Using this control together with other devices optimized for high-speed scanning, video-rate imaging of protein molecules in liquids is achieved.
Single shot measurements of laser driven shock waves using ultrafast dynamic ellipsometry
Authors: Bolme C. A. , McGrane S. D. , Moore D. S. , Funk D. J.
Published: August 2007

Ultrafast dynamic ellipsometry, a diagnostic that measures both the shock-induced optical effects and the motion of shocked materials, has been implemented in a single shot form. This is accomplished using chirped pulse interferometry and probing the sample at two angles with both s- and p-polarized light. The application of single shot ultrafast dynamic ellipsometry should prove important in future studies of shocked transparent materials and metals because it allows concurrent determination of the initial and shocked optical constants, shock and particle velocities, and the picosecond time dependence of these properties with a higher signal-to-noise ratio and less stringent sample requirements than multishot methods. The ability to infer both the initial and shocked refractive indices of the material eliminates the need for performing extra experiments to calibrate the window, greatly simplifying the analysis and making each shot a self-contained experiment. The implementation of this diagnostic is described, and its utility is demonstrated on a shocked thin film of polycarbonate. Analysis of the data employs a multilayer thin film model to calculate the reflectance as a function of the time-dependent layer thicknesses and optical properties. Hugoniot data for the thin film polycarbonate is presented along with the effect of shock compression on the refractive index, which is consistent with the Gladstone-Dale relation.
Weak-Hamiltonian dynamical systems
Authors: Vaisman Izu
Published: August 2007

A big-isotropic structure E is an isotropic subbundle of TM⊕T*M, endowed with the metric defined by pairing. The structure E is said to be integrable if the Courant bracket [X,Y]∊ΓE, ∀X,Y∊ΓE. Then, necessarily, one also has [X,Z]∊ΓE⊥, ∀Z∊ΓE⊥ [Vaisman, I., “Isotropic subbundles of TM⊕T*M,” Int. J. Geom. Methods Mod. Phys. 4, 487–516 (2007)]. A weak-Hamiltonian dynamical system is a vector field XH such that (XH,dH)∊ΓE⊥(H∊C∞(M)). We obtain the explicit expression of XH and of the integrability conditions of E under the regularity condition dim(prT*ME)=const. We show that the port-controlled, Hamiltonian systems (in particular, constrained mechanics) [Dalsmo, M. and van der Schaft, A. J., “On representations and integrability of mathematical structures in energy conserving physical systems,” SIAM J. Control Optim. 37, 54–91 (1998)] may be interpreted as weak-Hamiltonian systems. Finally, we give reduction theorems for weak-Hamiltonian systems and a corresponding corollary for constrained mechanical systems.
Nuclear targeting of the growth hormone receptor results in dysregulation of cell proliferation and tumorigenesis
Authors: Conway-Campbell Becky L. , Wooh Jong Wei , Brooks Andrew J. , Gordon David , Brown Richard J. , Lichanska Agnieszka M. , Chin Hong Soon , Barton Chenoa L. , Boyle Glen M. , Parsons Peter G. , Jans David A. , Waters Michael J.
Published: August 2007

Growth hormone receptor (GHR) has been demonstrated to be nuclear localized both
in vivo
and
in vitro
, but the significance of this observation has remained elusive. Here we show that nuclear GHR is strongly correlated with proliferative status
in vivo
by using a liver regeneration model.
In vitro
, nuclear translocation of the GH receptor is GH-dependent and appears to be mediated by the Importin system. Constitutive nuclear targeting of GHR in murine pro-B cells is associated with constitutive activation of STAT5, a transforming agent in lymphoma and other cell types. This activation is abrogated by inhibition of JAK2 and appears to be driven by autocrine murine GH action coupled with enhanced nuclear uptake of phospho-STAT5. Nuclear targeting induces dysregulated cell cycle progression in the pro-B cell line, associated with constitutive up-regulation of the proliferation inducers
Survivin
and
Mybbp
, the metastasis related
Dysadherin
, and other tumor markers. GHR nuclear-targeted cells generate aggressive metastatic tumors when injected into nude mice, which display nuclear localized GHR strikingly similar to that seen in human lymphomas. We conclude that aberrant nuclear localization of GHR is a marker of high proliferative status and is sufficient to induce tumorigenesis and tumor progression.
Hippocampal differentiation without recognition: An fMRI analysis of the contextual cueing task
Authors: Greene Anthony J. , Gross William L. , Elsinger Catherine L. , Rao Stephen M.
Published: August 2007

A central role of the hippocampus is to consolidate conscious forms of learning and memory, while performance on implicit tasks appears to depend upon other structures. Recently, considerable debate has emerged about whether hippocampal-dependent tasks necessarily entail task awareness. In the contextual cueing task, repetition facilitation is implicit, but impaired in patients with amnesia. Whether the hippocampus alone or other MTL structures are required is unclear. Event-related functional magnetic resonance imaging revealed hippocampal activity that differentiates novel from repeated arrays. This pattern of results was observed without recognition of the repeating arrays. This finding provides support for the claim that the hippocampus is involved in processes outside the domain of conscious learning and memory.
The effects of electromyographic activity on the accuracy of the Narcotrend® monitor compared with the Bispectral Index during combined anaesthesia
Authors: Panousis P. , Heller A. R. , Burghardt M. , Bleyl J. U. , Koch T.
Published: August 2007

The Narcotrend® is a monitor system for the assessment of depth of anaesthesia. The objective of this trial was to investigate the susceptibility of the Narcotrend to electromyographic (EMG) activity when compared with the Bispectral Index (BIS). We enrolled 33 patients undergoing major urological procedures under combined anaesthesia (thoracic epidural analgesia and general anaesthesia). Anaesthetic depth was assessed simultaneously by the BIS XP and Narcotrend. The intended anaesthetic depth ranged between 40 and 55 in the BIS and between D2 and D0 in the Narcotrend. BIS, but not Narcotrend, values correlated significantly (p < 0.0001) with EMG. BIS values between 70 and 80 occurred intermittently above an EMG activity of 35 dB, whereas the Narcotrend and the clinical signs remained unchanged during the period of elevated BIS values. None of the patients reported intra‐operative awareness. Increased electromyographic activity does not affect Narcotrend values. Under combined anaesthesia, the Narcotrend monitor is more reliable when compared with the BIS regarding susceptibility to increased EMG activity.
The effect of dilution and prolonged injection time on fentanyl‐induced coughing*
Authors: Yu H. , Yang X.‐Y. , Zhang X. , Li Q. , Zhu T. , Wang Y. , Liu B.
Published: August 2007

This study was designed to evaluate the effect of diluting fentanyl 50 μg.ml−1 to 25 or 10 μg.ml−1 with 0.9% saline and prolonged injection time on fentanyl‐induced cough. Two hundred patients requiring general anaesthesia were randomly allocated into four groups: 50 μg.ml−1 (Group I), 25 μg.ml−1 (Group II), 10 μg.ml−1 (Group III) or 10 μg.ml−1 combined with prolonged injection (Group IV). Fentanyl 3 μg.kg−1 was administered within 5 s in Groups I, II, and III, or over 30 s in Group IV. Occurrence of cough was significantly reduced in Group IV (2% vs 32%, 16% and 12% in Groups I, II and III, respectively, p < 0.05). There were no statistically significant differences in the severity of coughing between the four groups (p > 0.05). We conclude that dilution of fentanyl to 10 μg.ml−1 with 0.9% saline combined with a prolonged injection time eliminates fentanyl‐induced cough.