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BACKGROUND: Pancreatic cancer presents as advanced disease in >80% of patients; yet, appropriate ages to consider prevention and early detection strategies are poorly defined. We investigated age-specific associations and attributable risks of pancreatic cancer for established modifiable and non-modifiable risk factors. PATIENTS AND METHODS: We included 167 483 participants from two prospective US cohort studies with 1190 incident cases of pancreatic cancer during >30 years of follow-up; 5107 pancreatic cancer cases and 8845 control participants of European ancestry from a completed multicenter genome-wide association study (GWAS); and 248 893 pancreatic cancer cases documented in the US Surveillance, Epidemiology, and End Results (SEER) Program. Across different age categories, we investigated cigarette smoking, obesity, diabetes, height, and non-O blood group in the prospective cohorts; weighted polygenic risk score of 22 previously identified single nucleotide polymorphisms in the GWAS; and male sex and black race in the SEER Program. RESULTS: In the prospective cohorts, all five risk factors were more strongly associated with pancreatic cancer risk among younger participants, with associations attenuated among those aged >70 years. The hazard ratios comparing participants with three to five risk factors with those with no risk factors were 9.24 [95% confidence interval (CI) 4.11–20.77] among those aged ≤60 years, 3.00 (95% CI 1.85–4.86) among those aged 61–70 years, and 1.46 (95% CI 1.10–1.94) among those aged >70 years (P(heterogeneity) = 3×10(−5)). These factors together were related to 65.6%, 49.7%, and 17.2% of incident pancreatic cancers in these age groups, respectively. In the GWAS and the SEER Program, the associations with the polygenic risk score, male sex, and black race were all stronger among younger individuals (P(heterogeneity) ≤0.01). CONCLUSIONS: Established risk factors are more strongly associated with earlier-onset pancreatic cancer, emphasizing the importance of age at initiation for cancer prevention and control programs targeting this highly lethal malignancy.

China is one of the largest stripe rust epidemic areas in the world. Central Shaanxi, an important overwintering region, serves as a ‘bridge’ between the western over-summering and eastern epidemic regions. Understanding of resistance levels and Yr-gene distribution in regional wheat breeding lines may provide valuable recommendations for releasing resistant cultivars for managing the disease. A total of 183 wheat breeding lines developed for central Shaanxi were tested for seedling resistance to nine Chinese races of Puccinia striiformis f. sp. tritici (Pst) in the greenhouse. In field tests, entries were evaluated for stripe rust resistance in Yangling, Shaanxi, an overwintering region for the pathogen and artificially inoculated with selected races. In Tianshui, Gansu Province, an over-summering region, entries were evaluated under natural infection of Pst. Molecular markers for Yr5, Yr9, Yr10, Yr15, Yr17, Yr18, Yr26 and Yr61 were used to determine the presence and absence of the genes. Among t...

Bus priority is the effective methods of reducing traffic jam in large and medium-sized cities. Application and assessment of bus signal priority is studied, bus signal priority whole scheme is put forward based on GPS pointing and intelligent dispatch by investigating the situation of No.36 bus waiting time at stops and intersections. Based on Zigbee active request bus signal priority, dataflow process under local request and central request is analyzed, the principle of bus signal priority on balanced distance headway is put forward, and adjustment of key features parameters realized combining with SCATS traffic signal control system. The application assessment shows that, there are average 651 priority requests and 286 priority buses every day, priority efficiency is 43.9%.The average speed of No.36 bus increased 15.8%, the delay time reduced 13.2%, the stopping times reduced 27%, the twice stop situation at intersections basically disappeared, average delay at each intersection increased 3%.

In this paper, the crustal horizontal velocity fields of the Weihe Basin and the Xi'an area are determined using high-precision GPS campaign measurements, which in turn provide constraints to calculate tectonic stress fields. A finite element dynamic model is employed for the Weihe Basin and an elastic block model for the Xi'an area. It is suggested that the ground fissures in the Weihe Basin are shaped by active faults under the effect of a NW-SE regional tension stress field. Fault motion is the fundamental factor influencing the ground fissures and controls their directions and distribution, though the excessive extraction of underground water might be another major factor that accelerates the development of ground fissures. It is believed the results obtained in this study can provide important information for the prevention of basin ground fissure disasters and aid urban construction.

Pure aluminum electrodes were treated in alkaline stannate solutions, and the effects of some factors such as NaOH content and treating time were explored. The corrosion and electrochemical performances of the modified aluminum anodes in 4.0 M KOH methanol-water mixed solutions containing a methanol/water volume ratio of 7:3 (30% water) with and without stannate were investigated by means of hydrogen collection, polarization curve, galvanostatic discharge, scanning electron microscopy (SEM), and energy dispersive analysis of X-ray (EDAX). Metallic tin with high hydrogen evolution overpotential was deposited in aluminum surfaces by the modification treatments using stannate, resulting in the relatively low corrosion rate and markedly enhanced discharge performance of the modified aluminum anodes. In our experimental range the aluminum electrode treated in the solution with 0.1 M NaOH for 30 min showed lower corrosion rate and better discharge performance. The addition of Na(2)SnO(3) in 4.0 M KOH methanol-water mixed solutions with 30% water inhibited the corrosion of the aluminum electrodes modified in the treating solution with 0.1 M NaOH for 30 min, resulting from the deposition of tin with high hydrogen evolution overpotential in aluminum surfaces. The deposition of metallic tin on the electrode surface and the existence of stannate in the electrolytes were responsible for the notable enhancement in the discharge performance of the modified aluminum anode. (C) 2010 Elsevier B.V. All rights reserved.

We report analyses of B isotopic compositions in water and suspended particulate matter collected in the Changjiang and its main tributaries. We showed that four sources control the dissolved boron budget; namely atmospheric deposition, evaporite dissolution, anthropogenic inputs and silicate weathering. The contribution of silicate weathering to the dissolved B load ranges from 40% to 50% for the Changjiang main channel and from 45% to 88% for the main tributaries. The isotopic composition of dissolved boron derived from silicate weathering range from −3‰ up to +9‰ suggesting that isotopic fractionation occurs during silicate weathering. The boron isotopic composition of suspended particulate matter range from −11.4‰ to −6‰. Boron derived from silicate weathering is preferentially carried out by the dissolved load which accounts for 30–96% of the total boron. We show that the isotopic compositions of both the dissolved load and suspended particulate matter are controlled by the competition between boron leaching and boron uptake into secondary phases. The first process is characterized by a loss of boron relative to the bedrock without apparent isotopic fractionation whereas the last one is associated to a large isotopic fractionation which enriches the dissolved boron in heavy isotope.

This study focuses on the chemical and Sr isotopic compositions of the dissolved load of the rivers of the Changjiang Basin, one of the largest riverine systems in the world. Water samples were collected in August 2006 from the main tributaries and the main Changjiang channel. The chemical and isotopic analyses indicated that four major reservoirs (carbonates, silicates, evaporites and agriculture/urban effluents) contribute to the total dissolved solutes. The overall chemical weathering (carbonate and silicate) rate for the Changjiang is approximately 40 ton/km2/year or 19 mm/kyr, similar to that of the Ganges–Brahmaputra system, and the basin is characterized by carbonate and silicate weathering rates ranging from 17 to 56 ton/km2/year and from 0.7 to 7.1 ton/km2/year, respectively. In the lower reach of the Changjiang main channel, the weathering rates are estimated to be 36 and 2.2 ton/km2/year for carbonates and silicates, respectively. It appears that sulphuric acid may dominate chemical weathering reactions for some sub-basins. The budgets of CO2 consumption are estimated to be 646 × 109 and 191 × 109 mol/year by carbonate and silicate weathering, respectively. The contribution of the anthropogenic inputs to the cationic TDS of the Changjiang is estimated to be 15–20% for the most downstream stations. Our study suggested that the Changjiang is strongly impacted by human activities and is very sensitive to the change of land use.

Novel carbon coils were synthesized by an arc discharge process on a metal plate under different gas pressures from 160 to 460 Torr. The morphology and yield of carbon coils were examined by scanning (SEM) and transmission (TEM) electron microscopy. The influence of the gas pressure and impurities such as sulfur and phosphorus on the growth of product is also discussed. It was demonstrated that the morphology and yield of the coils were greatly controlled by the gas pressure. On the other hand, a new model was proposed to describe the coil growth. Our method offers a preferable alternative for the efficient, abundant and economical growth of carbon coils.

The Korea Superconducting Tokamak Advanced Research (KSTAR) project is the major effort of the national fusion programme of the Republic of Korea. Its aim is to develop a steady state capable advanced superconducting tokamak to establish a scientific and technological basis for an attractive fusion reactor. The major parameters of the tokamak are: major radius 1.8 m, minor radius 0.5 m, toroidal field 3.5 T and plasma current 2 MA, with a strongly shaped plasma cross-section and double null divertor. The initial pulse length provided by the poloidal magnet system is 20 s, but the pulse length can be increased to 300 s through non-inductive current drive. The plasma heating and current drive system consists of neutral beams, ion cyclotron waves, lower hybrid waves and electron cyclotron waves for flexible profile control in advanced tokamak operating modes. A comprehensive set of diagnostics is planned for plasma control, performance evaluation and physics understanding. The project has completed its conceptual design and moved to the engineering design and construction phase. The target date for the first plasma is 2002.

Abstract The Knoevenagel condensation of substituted benzaldehydes with active methylene compounds was performed very efficiently by using a USY (ultrastable Y) zeolite as heterogeneous catalyst.

The liquid phase Friedel-Crafts acylation of anisole with alkanoic acids, anhydrides and substituted benzoic acids, respectively, over zeolites was studied in detail. The acylation with substituted benzoic acids, as well as with alkanoic acids, could be successfully performed over zeolite catalysts. When car☐ylic acids were used as acylating agents, the activity of the Y zeolite increased with its Lewis acidity, showing that the Lewis acid sites were more active than the Bronsted acid sites. The mechanism of the reaction was found to be similar to the case of homogeneous catalysis, that is, the electrophilic intermediate formed from the acylating agent over zeolite acid sites attacked at the aromatic ring of anisole. However, the structure of the electrophilic intermediate would depend upon the acylating agent and the nature of zeolite acid sites. The anhydride would transform into the acylium cation, but the car☐ylic acid would lead to the protonated and coordinated car☐ylic acid as the electrophiles over Bronsted and Lewis acid sites of the zeolites, respectively. The protonated car☐ylic acid would preferentially attack at the oxygen atom of anisole and give phenyl car☐ylic ester, while the coordinated car☐ylic acid and the acylium cation would predominantly react with the aromatic ring, leading to the Friedel-Crafts acylation product 4-acyl anisole.

We address the problem of control of uncertain systems with time delays. Using the fuzzy logic control and artificial neural network methodologies, we present a self-learning fuzzy neural control scheme for general uncertain processes. In this scheme, a neural network compensator is designed instead of the classical Smith predictor for attenuating the adverse effects of time delays of the uncertain systems. The scheme has been used in control of welding pool dynamics of the arc welding process, and the experiment results show the control scheme available.

The synthesis of ethyl, n-butyl, isopentyl and benzyl acetates, ethyl and n-butyl benzoates and dioctyl phthalates was achieved by using a H-ZSM-5 and two HY zeolites as catalysts under conditions similar to the classical case with sulfuric acid catalyst. A high yield of acetates was obtained with essentially 100% selectivity. HY was an excellent catalyst for the synthesis of phthalates. The production of benzoates on the zeolite catalysts was slow, though zeolite HY with high Si/Al ratio would seem a useful catalyst for this difficult esterification reaction.

A damage model of low cycle shear fatigue has been developed in dislocation theory. On the basis of this model, a formula including the factors of thermal cycle temperature, dwell time, and atmospheric oxidation has been established to predict the life of surface mount technology (SMT) solder joints under thermal cycling. This formula has been verified by experiments on the specimens of actual SMT assemblies. The results show that the life formula established coincides with the experimental results. >

The hydrothermal treatment of a (NH4)0.8Na0.2Y zeolite was carried out in a flow reactor in order to determine quantitatively the effect of the operating conditions (time, temperature, water pressure) on the dealumination of this zeolite. X-ray diffraction was used to follow the process of dealumination and to characterize the variations of the crystallinity. The enrichment of the outer surface in Al was measured by X-ray photoelectron spectroscopy (XPS). First the temperature of the zeolite was raised rapidly to the temperature chosen for the hydrothermal treatment (260 to 820°C) under nitrogen flow. During this rise in temperature there was a significant dealumination caused by water physically adsorbed or liberated by dehydroxylation. This dealumination is accompanied by a partial collapse of the zeolite framework. After the ceiling temperature was reached, the zeolite was submitted to a flow of water vapor. Two periods could be distinguished, namely an initial one in which dealumination was rapid, and a second one in which it was slow. Only the aluminum atoms with which NH4+ (and not Na+) are associated could be extracted from the framework. For both periods the kinetic orders with respect to these aluminum atoms and to water are equal to 1; the apparent activation energy is about 20 kJ mol−1 for the rapid dealumination and 70 for the slow process. The first period would correspond to the dealumination of the protonic zeolite and the second to that of the zeolite exchanged by cationic aluminum species. Under high water pressure (>50 kPa) there is a relationship between zeolite dealumination and subsequent migration of extra-framework aluminum species to the outer surface of the crystallites. However, these processes are independent. Indeed during the self-steaming of the zeolite, dealumination occurs without enrichment in Al of the outer surface.

A series of samples with different chemical Si Al ratios (3–7.2) and crystallinities above 80% were prepared by dealumination of a NH4NaY zeolite with different amounts of ammonium hexafluorosilicate (from 0.25 to 1.15 the stoichiometric hexafluorosilicate/zeolite ratio). With all the samples, the Si Al ratio on the outer surface of the crystallites (measured by XPS) was much greater than was the Si Al ratio determined by chemical analysis. The chemical Si Al ratio was slightly greater than was the framework Si Al ratio estimated by X-ray diffraction or measured by 29Si n.m.r. For the most dealuminated sample, the concentration profile of Si and Al was determined through a combined XPS-SIMS study down to about 40 nm. It can be concluded that the gradient in the Si Al ratio in the crystallites was due both to a gradient of dealumination (dealumination is diffusion controlled) and to a selective deposit of silica on the outer surface.

The dealumination of a NH4NaY zeolite through hydrothermal treatment at 500 ° C and 650 ° C occurs apparently through a kinetic law of the second order with respect to aluminium. The kinetic order is actually equal to one when the hydrolyzable aluminium atoms only are taken into account i.e. those to which ammonium ions and not sodium ions are associated.

Une quinzaine d'echantillons de zeolithes Y ont ete prepares par simple ou double traitement a haute temperature (540 a 820 °C) avec ou sans addition d'eau d'une zeolithe NH4 NaY. La cristallinite des echantillons est caracterisee par adsorption d'azote ou par diffraction X, la composition de la charpente zeolithique par RMN cu 29 Si, par diffraction X (parametre de maille) et par IR (bandes de structure). Les parametres determinant la cristallinite et le taux de desalumination sont notamment la temperature de traitement, la pression de vapeur d'eau et la teneur en sodium de la zeolithe. On montre en particulier que quelles que soient les conditions de traitement, la cristallinite ne diminue fortement qu'aux fortes valeurs du taux de desalumination calcule en ne tenant pas compte des aluminiums lies aux sodiums.

This paper presents a self-learning fuzzy neural control scheme for a complicated object-an arc welding process. In this scheme, an analytical formula of fuzzy controller is used for adaptively regulating the fuzzy rules, and a neural network model is used for real-time learning dynamics of the uncertain process. The scheme has been used in control of welding pool dynamics of the arc welding process, and experiment results show the effectiveness of the control scheme.

This paper presents a viscoelastic model for analysing the mechanical behaviour of SnPb solders which has been developed by combining grain boundary slip with viscoelasticity theory. On the basis of the model, and by using Boltzmann's integral constitutive equation of viscoelasticity, the mechanical behaviour (i.e., the relationships between stress (load) and strain (displacement)) of SnPb solders for one‐dimensional shearing deformation has been investigated and experimentally verified.

The number of washes with boiling water of a Y zeolite dealuminated with ammonium hexafluorosilicate strongly affects its stability under hydrothermal conditions. Traces of hexafluorosilicate, difficult to eliminate completely through washing, would be responsible for this effect. Hydrothermal treatments of mixtures of NH4NaY zeolite and of ammonium hexafluorosilicate (0.2-2 wt%) allow confirmation of this point.