Tweet Coupling: a social media methodology for clustering scientific publications

Scientometrics - We argue that classic citation-based scientific document clustering approaches, like co-citation or Bibliographic Coupling, lack to leverage the social-usage of the scientific...     

Effect of endoscopic sphincterotomy on gallbladder motility

In experimental animals, sphincterotomy facilitates passage of solids from the gallbladder and inhibits gallstone formation apparently by improvement in gallbladder emptying. In humans, however, gallbladder emptying has not been studied following endoscopic sphincterotomy (ES) in patients with gallstones. We therefore prospectively studied resting and cerulin-stimulated gallbladder volumes by real time ultrasonography in 15 patients of choledocholithiasis with gallbladder in situ (eight with and seven without gallbladder calculi) before and after (after bile duct clearance) ES. ES significantly lowered resting gallbladder volume (21.2 +/- 10.6 vs 11.1 +/- 5.0; P < 0.0001) and cerulin-stimulated residual gallbladder volume (10.8 +/- 5.6 vs 4.4 +/- 2.1; P < 0.0001). ES also significantly increased the gallbladder ejection fraction (47.3 +/- 12.1% vs 58.8 +/- 11.1%; P < 0.0001). The rate constant for gallbladder emptying after cerulin infusion also increased significantly after ES (-0.022/min vs -0.031/ min; P < 0.0001). Significant improvement in gallbladder motility was observed in both groups of patients with and without gallbladder calculi. ES significantly improves gallbladder motility in humans.     

Efficacy of Biofilms under Toxic Conditions

Response of biofilms to toxic compounds has been modeled using Monod-type inhibition kinetics. Biofilm inhibition due to substrate, secondary substrate, and product is considered. For biofilm inhibition due to substrate and secondary substrate with high inhibitory substances, the model predicted the biofilm effectiveness factor to be higher than unity. On the other hand, for slightly inhibitory substances, substrate limitations within the biofilm due to mass transfer resistance resulted in a reduction in biofilm effectiveness factor as its thickness increased. In case of product inhibition, the effectiveness factor of the biofilm was always lower than one due to accumulation of product leading to higher concentrations within the biofilm than in the bulk. The generalized models developed for effectiveness factors under various conditions of inhibition can be used as a predictive tool in design of wastewater treatment systems.     

Comparison of ambient and spray aerosol deposition in a standard induction port and more realistic mouth–throat geometry

For inhalation aerosols, it is well known that spray momentum and geometry characteristics can significantly influence deposition in the mouth–throat (MT) region. However, little is know about the quantitative influence of spray momentum on aerosol transport and deposition. The objective of this study was to evaluate the effect of spray momentum on deposition in a standard induction port (IP) and a representative MT geometry using capillary-generated aerosols. Capillary aerosol generation (CAG) was selected as a model spray aerosol system that has not been previously tested in a realistic throat geometry. To evaluate the effects of spray momentum, the transport and deposition characteristics of transient capillary-generated aerosols were compared with ambient particles of the same size inhaled at a steady flow rate of 30 L/min. To evaluate the influence of geometry, aerosols were considered in a standard IP and a more realistic MT model. A previously tested CFD model was employed to simulate aerosol transport and deposition for ambient and CAG spray aerosols in both the IP and MT geometries. Considering the capillary-generated spray, good agreement was observed for the deposition of drug mass between the in vitro experiments (IP—15.3%, MT—19.4%) and CFD model predictions without droplet evaporation (IP—14.7%, MT—20.8%). In all cases considered, deposition was increased for spray vs. ambient aerosols and in the MT geometry vs. the IP model. Based on CFD results for a representative polydisperse aerosol distribution, the deposition of ambient particles was highly sensitive to the geometry considered, with 2.9 times more deposition in the MT compared to the IP model. In contrast, deposition was less influenced by the geometry for a CAG spray aerosol, with only a 25–40% deposition increase in the MT. As a result, use of the simple IP model may provide a reasonable approximation of total MT deposition for systems with high spray momentum. However, the IP model may be less useful for evaluating the total MT deposition in systems with reduced spray momentum effects.     

Effect on Diamagnetism and Phonon Modes due to Mg and Be Doping at Ca Sites in Cu0.5Tl0.5Ba2Ca3?yMyCu4O12?δ (y=0 and 1.5 for M=Mg, Be) High Temperature Superconductors

We synthesized as prepared and oxygen annealed Cu_0.5Tl_0.5Ba₂Ca_3−y M _y Cu₄O_12−δ (y=0 and 1.5 for M=Mg, Be) High Temperature Superconductors (HTSCs) by using the solid state reaction method. It is observed that superconducting properties and the magnitude of the diamagnetism are enhanced by the doping of Mg and Be at the Ca site; this is due to smaller ionic sizes and higher electronegativities of Mg and Be as compared to Ca. Furthermore, interplanar coupling is also improved and shrinking of the axis length is the direct evidence of it. The carrier’s concentration in conducting planes is improved by carrying out post-annealing experiments in the oxygen atmosphere. Moreover, FTIR absorption measurements are also incorporated.     

联合国开发计划署对城市管理项目的支持——将全球性项目参与者与地方实际相结合

调整全球性结构体系，使之能对地方性的需求作出响应，这一点是近来全球发展合作史上最为显著的一个趋势。在联合国成立的第60个年头，它从整体上来说已经不仅仅是各国中央政府的俱乐部，而是日益成为社会各界需求的收集者和促成者。     

Potential alternatives of heat and power technology application using rice straw in Thailand

Rice straw could be used for heat and power with the current technologies available in Thailand. The cost of rice straw for power generation at 0.38–0.61 Baht/MJ_e (at rice straw price 930–1500 Baht/t) is not competitive with coal at 0.30 Baht/MJ_e but comparable with other biomass at 0.35–0.53 Baht/MJ_e. However, utilization of rice straw in industrial boilers is a more competitive and flexible option with two alternatives; (1) installing rice straw fired boilers instead of heavy oil fired or natural gas ones when selecting new boilers; and (2) fuel switching from coal to rice straw for existing boilers with cost saving of feedstock supply by 0.01 Baht/MJ_h. Based on its properties (Slagging index, R_s = 0.04; fouling index, R_f = 0.24), rice straw is not expected to have significant operating problems or different emissions compared with wheat straw and rice husk under similar operating conditions.     

Homogeneous and heterogeneous precipitation mechanisms in a binary Mg–Nd alloy

Parallel modes of precipitation mechanisms in an Mg–Nd alloy were revealed by examining an isothermally annealed high pressure die cast alloy at 177 °C for up to 100 h. Broadly, precipitate evolution was observed to occur concurrently on dislocations and within the surrounding α-Mg matrix. However, it was observed that the presence of dislocation accelerated the precipitate formation kinetics significantly. In contrast to the accepted precipitation pathway in the Mg–Nd system, i.e., SSSS → GP zones → β″ → β′ → β₁ → β → β_e, dislocations were found to preferentially facilitate the formation of β′ and β₁ precipitates even at the very early stages (5 h) of annealing. Within the same time frame, a homogeneous distribution of Nd-rich pockets was observed throughout the α-Mg matrix, along with the β′ and β₁ precipitates decorating dislocation lines. Results further indicate that these Nd-rich regions initiated precipitation within the parent α-Mg matrix. The formation of these Nd-rich pockets was explained on the basis of a miscibility gap in the α-Mg phase at 177 °C. Our results demonstrate that the presence of dislocations influence strongly the phase-transformation pathways in Mg-rare earth alloys by facilitating the formation of selective precipitate phases.     

Experimental assessment of a clamp actuation intensity analysis model

The application of a clamp actuation intensity analysis (CAIA) model is a rough cut technique used to compute the minimum clamp pre-loads necessary to keep a workpiece from slipping within a fixture throughout a machining cycle. A CAIA model is based on the simplistic assumption that a fixture-workpiece behaves as a system of contacting rigid bodies subject to Coulomb friction at the joints. To date, little research has been carried out to ascertain how well these models predict minimum pre-loads for actual applications, or how their limitations can be overcome in order to improve their performance. This paper describes an experimental study that was used to the assess: (1) the impact of including all contact regions, regardless of rigidity, within a CAIA model, (2) the sensitivity of the CAIA model to known variations in coefficient of friction, and (3) the accuracy of predicted pre-loads for actual milling operations. The major conclusions drawn from this study are: (1) only the stiffest contact regions of a fixture-workpiece system should be included in a CAIA model, (2) there is nearly a one-to-one correspondence between the variation of the clamp pre-loads computed by the CAIA model and the variation of the inputted friction coefficients, (3) the clamp pre-loads computed by the CAIA model for a series of milling experiments were within 25% of the actual values for the majority of experiments, and (4) a reduction in the coefficient of static friction at fixture-workpiece joints appears to occur during the application of milling forces, this is especially true for planar tip fixture elements.     

Full chain energy analysis of biodiesel from Jatropha curcas L. in Thailand

Biodiesel production from Jatropha curcas Linnaeus (JCL) has been considered for partial substitution of diesel fuel for transportation in Thailand. The aim of this study is to investigate the energy consumption for long-term investment (20 years) of Jatropha Methyl Ester (JME) production in Thailand using a life cycle approach. Apart from the average result, two scenarios--best and worst case--are set up to illustrate the range of results due to the variety of management practices. The main contributors to the energy use are JCL cultivation, transesterification, and transportation process. The net energy gain (NEG) and net energy ratio (NER) of biodiesel and coproducts from the life cycle of JCL are 4720 GJ/ha and 6.03, respectively. Even if only biodiesel is considered without coproducts, the NER is 1.42, still higher than 1. The study will support decision makers in the energy policy sector to make informed decisions vis-a-vis promotion of JCL plantations for biodiesel.