Sulbactam/ampicillin in comparison with cefuroxime for infections of the lower respiratory tract. Results of a prospective, randomized comparative study

Gallbladder removal using laparoscopic techniques has rapidly been adopted by surgeons around the world. Questions have been raised concerning laparoscopic cholecystectomy, including the safety of the operation, its implications for management of common bile duct stones, and the means by which surgeons should be trained. In the present series, 424 patients were referred to a single surgeon for cholecystectomy during a 22-month period. A traditional open cholecystectomy was performed in 9 patients (2.1%) because of presumed contraindications to laparoscopic cholecystectomy. Laparoscopic cholecystectomy was attempted in the remaining 415 patients (97.9%). On the basis of preoperative investigations, 19 patients (4.6%) underwent endoscopic retrograde cholangiopancreatography. Endoscopic sphincterotomy and stone extraction were performed in the 13 patients (3.1%) demonstrating choledocholithiasis. Laparoscopic cholecystectomy was converted to an open operation in 8 patients (1.9%) owing to dense adhesions, obscure anatomy, or cholangiographic abnormalities. Laparoscopic cholecystectomy was successfully performed in 407 patients (96%) in 95 +/- 2 minutes (mean +/- SEM). Surgical trainees were involved in all operations and performed 68% of the procedures under supervision. Cystic duct cholangiograms were obtained selectively in 129 patients (30.4%). Intraoperative complications occurred in 3 patients, including 1 patient with a minor injury to the common bile duct (0.2%). There was no perioperative mortality, and major complications occurred in 6 patients (1.4%). Minor complications were seen in 12 others (2.8%), and one patient required reoperation for a trocar injury to the jejunum. Prolonged follow-up has revealed one case of asymptomatic retained common bile duct stones (0.2%). Laparoscopic cholecystectomy can therefore be performed in more than 95% of patients with no mortality and minimal morbidity.(ABSTRACT TRUNCATED AT 250 WORDS)     

Colloid Science of Metal Nanoparticle Catalysts in 2D and 3D Structures. Challenges of Nucleation, Growth, Composition, Particle Shape, Size Control and Their Influence on Activity and Selectivity

Recent breakthroughs in the synthesis of nanosciences have achieved the control of size and shape of nanoparticles that are relevant for catalyst design. In this article, we review advances in the synthesis of nanoparticles, fabrication of two- and three-dimensional model catalyst systems, characterization, and studies of activity and selectivity. The ability to synthesize monodispersed platinum and rhodium nanoparticles 1–10 nm in size permitted us to study the influence of composition, structure, and dynamic properties of monodispersed metal nanoparticles on chemical reactivity and selectivity. We review the importance of the size and shape of nanoparticles to determine reaction selectivity in multi-path reactions. The influence of metal–support interaction has been studied by probing the hot electron flows through the metal–oxide interface in catalytic nanodiodes. Novel designs of nanoparticle catalytic systems are also discussed.     

Groundwater Allocation Using a Groundwater Level Response Management Method—Gnangara Groundwater System, Western Australia

The Gnangara groundwater system (Gnangara system) is an important source of groundwater for Perth, Western Australia: in the order of 350 GL of groundwater is abstracted annually. The Gnangara system also sustains groundwater dependent ecosystems (GDEs), mostly wetlands and native vegetation. Declining groundwater levels across the system have led to impacts on a number of key GDEs. Western Australia’s Department of Water recently prepared a Water Management Plan for the Gnangara system. Allocation limits were reviewed as part of the plan preparation. To assist in reviewing allocation limits, an adaptive Groundwater Level Response Management (GWLRM) methodology was developed and implemented. This paper describes the methodology and its application to the Gnangara system. The methodology was developed to be used as a corrective tool for the short- and medium-term, to assist in achieving long-term sustainability of groundwater management in the context of changing climate and declining groundwater levels. The GWLRM methodology is based on groundwater storage depletion and can be applied to existing allocation limits as an interim tool to assist in making management decisions aimed at recovering groundwater resources. The key to the GWRLM correction is that it will direct water allocation towards sustainable levels on the basis of measured trends. Allocations corrected through application of the GWRLM would therefore represent interim and improved water allocation figures. GWLRM can also identify potential problem areas where the principles or calculations used for long-term sustainable groundwater allocation would need to be reviewed. For the Gnangara system, the calculated storage changes or GWLRM corrections were considered together with results of predictive modelling as part of an expert panel process to derive a more sustainable interim groundwater allocation regime while further research is being completed.     

Concept design of fusion power shutdown system for ITER

ITER is a nuclear facility. It is essential to maintain operational safety or to bring this facility to a safe state in case of accidents or incidents. During plasma operation ITER plasma will generate significant heat loads on the plasma facing components. For a few reference accidents there is the need to stop plasma reliably within a certain time. Fusion power shutdown system is the safety system to implement this termination function for ITER. It is based on the concept of massive gas injection.This paper summarizes the safety requirements, logics and the physics requirements on this system for reliable termination of ITER plasma. With regard to the quantity of gas, transient behavior simulation is shown, subsequently providing guideline for laboratory bench-testing. Conceptual engineering design of the system is given together with instrumentation and control specifications.     

Levels of family assessment: I. Family, marital, and parent–child interaction.

Families are complicated systems to assess and quantify, requiring that decisions be made regarding where to focus research. The authors examined 3 levels of family interaction: marital, parent–child, and whole family. Instruments included the McMaster Structured Interview of Family Functioning, the Family Assessment Device, the Mealtime Interaction Coding System, the Dyadic Adjustment Scale, and the Parent/Caregiver Involvement Scale. Results suggest that each measure, representing a unique combination of family level, informant, and setting, contained both independent variance and information redundant with other measures characterizing the family. The strengths of using a theoretical base, in this case the McMaster model of family functioning, and a multimeasure approach arc discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Molten aluminum alloy fuel fragmentation experiments

Experiments were conducted in which streams of molten aluminum alloys were injected into a 1.2 m deep pool of water. The parameters varied were (i) injectant material (8001 aluminum alloy and 12.3 wt% U-87.7 wt% Al), (ii) melt superheat (0 to 50 K), (iii) water temperature (313, 343 and 373 K) and (iv) size and geometry of the pour stream (5, 10 and 20 mm diameter circular and 57 mm annular). The pour stream fragmentation was dominated by surface tension with large particles ( 30 mm) being formed from varicose wave breakup of the 10-mm circular pours and from the annular flow off a 57 mm diameter tube. The fragments produced by the 5 mm circular jet were smaller ( 10 mm), and the 20 mm jet which underwent sinuous wave breakup produced 100 mm fragments. The fragments froze in 313 K water to form large solid particles with high voidage which would be readily coolable. However, in water ≥ 343 K the melt fragments did not freeze during their transit through 1.2 m of water and agglomerated into a melt pool at the bottom of the vessel.     

Morphological effects on the bulk polymerization of trioxane in the solid state by γ-radiation

The solid-state polymerization by γ-radiation and postpolymerization of bulk samples of trioxane has been investigated. Different thermal treatment results in radically different initial morphologies of the melt-crystallized trioxane which in turn have a profound influence on the yield and morphology of the resulting poly(oxymethylene) (POM). The polymerization yield increases in the following series: melt-crystallized trioxane with an “opaque” (small grains) morphology, as-grown needles, trioxane with a “quasi-transparent” morphology, and finally thermally oriented crystals. Furthermore, little additional POM is formed during repeated polymerization cycles. The observation of an extensive nodulation of the polymer fibrils when the yield is high is consistent with a multiple-stage growth model for the solid-state polymerization of trioxane.     

Evaluators of image reconstruction algorithms

An image reconstruction algorithm is supposed to present an image that contains medically relevant information that exists in a cross section of the human body. There is an enormous variety of such algorithms. The question arises: Given a specific medical problem, what is the relative merit of two image reconstruction algorithms in presenting images that are helpful for solving the problem? An approach to answering this question with a high degree of confidence is that of ROC analysis of human observer performance. The problem with ROC studies using human observers is their complexity (and, hence, cost). To overcome this problem, it has been suggested to replace the human observer by a numerical observer. An even simpler approach is by the use of distance metrics, such as the root mean squared distance, between the reconstructed images and the known originals. For any of these approaches, the evaluation should be done using a sample set that is large enough to provide us with a statistically significant result. We concentrate in this paper on the numerical observer approach, and we reintroduce in this framework the notion of the Hotelling Trace Criterion, which has recently been proposed as an appropriate evaluator of imaging systems. We propose a definite strategy (based on linear abnormality-index functions that are optimal for the chosen figure of merit) for evaluating image reconstruction algorithms. We give details of two experimental studies that embody the espoused principles. Since ROC analysis of human observer performance is the ultimate yardstick for system assessment, one justifies a numerical observer approach by showing that it yields “similar” results to a human observer study. Also, since simple distance metrics are computationally less cumbersome than are numerical observer studies, one would like to replace the latter by the former, whenever it is likely to give “similar” results. We discuss approaches to assigning a numerical value to the “similarity” of the results produced by two different evaluators. We introduce a new concept, called rank-ordering nearness, which seems to provide us with a promising approach to experimentally determining the similarity of two evaluators of image reconstruction algorithms.