Abduction stress and AP weightbearing radiography of purely ligamentous injury in the tarsometatarsal joint

PURPOSE: This study was conducted to compare the efficacy of the Er-YAG laser sclerostomy ab externo versus trabeculectomy in the treatment of primary open-angle glaucoma. METHODS: Twelve patients with POAG underwent ab externo laser sclerostomy using an Er-YAG laser (Sklerostom 2.9; lambda = 2940 nm, t = 200 microseconds, 2 Hz, 400 microns, 15 mJ). Only local medication was used, and there were no risk factors for failure. As a control group 12 patients out of 248 standardized trabeculectomies were matched in terms of age, sex, diagnosis and local medications. No antimetabolites were used in either group. RESULTS: After a follow-up of 9 months in the sclerostomy group 53%; (7/12; P = 0.03) showed a patent fistula in comparison of 100% in the trabeculectomy group. There was a significantly lower mean IOP during the first postsurgical week in the group of sclerostomies (3.6 +/- 1.5 mmHg versus 7.5 +/- 2.7 mmHg; P = 0.0001) with a higher incidence of choroidal detachments (9/12 versus 2/12; P = 0.004). The choroidal detachments lasted longer in the sclerostomy group (3.5 months versus 0.3 months; P = 0.014). Iris incarcerations were found only in sclerostomies (7/12; P = 0.05). CONCLUSIONS: Based on these findings, Er-YAG laser sclerostomy prooved to be less effective than trabeculectomy in the treatment of glaucoma patients. Er-YAG laser sclerostomies were associated with a higher incidence of postsurgical complications such as hypotony, choroidal detachments and iris incarcerations. At this point Er-YAG laser sclerostomy is not superior to conventional trabeculectomy.     

ZipLine: an optimized algorithm for the elastic bulk synchronous parallel model

Machine Learning - The bulk synchronous parallel (BSP) is a celebrated synchronization model for general-purpose parallel computing that has successfully been employed for distributed training of...     

Pd3Ag(111) as a Model System for Hydrogen Separation Membranes: Combined Effects of CO Adsorption and Surface Termination on the Activation of Molecular Hydrogen

Topics in Catalysis - The co-adsorption of hydrogen and carbon monoxide on Pd3Ag(111) alloy surfaces has been studied as a model system for Pd-Ag alloys in membrane and catalysis applications using...     

Influence of the cross section shape on the behaviour of SRG-confined prismatic concrete specimens

The effectiveness of the steel-reinforced grout (SRG) jacketing technique in increasing both strength and deformation capacity has been substantiated by experimental evidence (Thermou and Pantazopoulou in Fib Struct Concr J 8: 35–46, 2007; Thermou et al. in ECCOMAS Thematic Conference, 2013; Thermou et al. in Mater Struct J, 2013). What it has not been addressed yet is the influence of the cross section shape on the behaviour of SRG-confined prismatic unreinforced concrete specimens. An experimental study was carried out where 18 concrete small scale specimens were tested to failure under concentric uniaxial compression load. A single layer of the steel-reinforced fabric was applied to circular, square and square specimens with rounded edges. Test results demonstrated that both strength and deformation capacity increased as the shape of the cross section changed from square to circular. In case of the square specimens, the gain in compressive strength was satisfying, whereas the ductility increase was more significant compared to that of the square specimens with rounded edges. An analytical expression for the lateral confining pressure exerted by the composite system was derived based on the assumption that the steel cords were treated as well-anchored steel stirrups placed at a distance equal to the spacing between the steel cords. The ability of the various steel and fiber-reinforced polymer confinement models from literature to predict the normalized compressive strength of non-circular specimens confined with SRG jackets was also explored.     

A message passing strategy for array redistributions in a torus network

The array redistribution problem occurs in many important applications in parallel computing. In this paper, we consider this problem in a torus network. Tori are preferred to other multidimensional networks (like hypercubes) due to their better scalability (IEE Trans. Parallel Distrib. Syst. 50(10), 1201–1218, [2001]). We present a message combining approach that splits any array redistribution problem in a series of broadcasts where all sources send messages of the same size, thus a balanced traffic load is achieved. Unlike existing array redistribution algorithms, the scheme introduced in this work eliminates the need for data reorganization in the memory of the source and target processors. Moreover, the processing of the scheduled broadcasts is pipelined, thus the total cost of redistribution is reduced.

Study of Coke and Coke Precursors During Catalytic Cracking of n-Hexane and 1-Hexene over Ultrastable Y Zeolite

In this paper we report about coke formation during catalytic cracking of n-hexane and 1-hexene over acidic ultrastable Y zeolite in a fixed-bed reactor. The study is based on a classification between coke precursors, whose amount is estimated through volatilisation by nitrogen purging, and coke, large formed coke molecules that remain during nitrogen purging even at 873 K and whose amount is estimated by oxidation at that temperature. The role of coke precursors on the coking process and catalytic cracking reaction is discussed as well as differences in coking tendencies between the two reactants. The results show that the amount of coke precursors and/or coke may decrease with reaction temperature resulting into a reversal of the coking dependence upon temperature.     

Computational Chemistry‐Guided Design of Selective Chemoresponsive Liquid Crystals Using Pyridine and Pyrimidine Functional Groups

Computational chemistry‐guided designs of chemoresponsive liquid crystals (LCs) with pyridine or pyrimidine groups that bind to metal‐cation‐functionalized surfaces to provide improved selective responses to targeted vapor species (dimethylmethylphosphonate (DMMP)) over nontargeted species (water) are reported. The LC designs against experiments are tested by synthesizing 4‐(4‐pentyl‐phenyl)‐pyridine and 5‐(4‐pentyl‐phenyl)‐pyrimidine and quantifying LC responses to DMMP and water. Consistent with the computations, pyridine‐containing LCs bind to metal‐cation‐functionalized surfaces too strongly to permit a response to either DMMP or water whereas pyrimidine‐containing LCs undergo a surface‐driven orientational transition in response to DMMP without interference from water. The computation predictions are not strongly dependent on assumptions regarding the degree of coordination of the metal ions but are limited in their ability to predict LC responses when using cations with mostly empty d orbitals. Overall, this work identifies a promising new class of chemoresponsive LCs based on pyrimidine that exhibits enhanced tolerance to water, a result that is important because water is a ubiquitous and particularly challenging chemical interferent in chemical sensing strategies based on LCs. The work also provides further evidence of the transformative utility of computational chemistry methods to design LC materials that exhibit selective orientational responses in specific chemical environments.     

Scalability of write-ahead logging on multicore and multisocket hardware

The shift to multi-core and multi-socket hardware brings new challenges to database systems, as the software parallelism determines performance. Even though database systems traditionally accommodate simultaneous requests, a multitude of synchronization barriers serialize execution. Write-ahead logging is a fundamental, omnipresent component in ARIES-style concurrency and recovery, and one of the most important yet-to-be addressed potential bottlenecks, especially in OLTP workloads making frequent small changes to data. In this paper, we identify four logging-related impediments to database system scalability. Each issue challenges different level in the software architecture: (a) the high volume of small-sized I/O requests may saturate the disk, (b) transactions hold locks while waiting for the log flush, (c) extensive context switching overwhelms the OS scheduler with threads executing log I/Os, and (d) contention appears as transactions serialize accesses to in-memory log data structures. We demonstrate these problems and address them with techniques that, when combined, comprise a holistic, scalable approach to logging. Our solution achieves a 20–69% speedup over a modern database system when running log-intensive workloads, such as the TPC-B and TATP benchmarks, in a single-socket multiprocessor server. Moreover, it achieves log insert throughput over 2.2 GB/s for small log records on the single-socket server, roughly 20 times higher than the traditional way of accessing the log using a single mutex. Furthermore, we investigate techniques on scaling the performance of logging to multi-socket servers. We present a set of optimizations which partly ameliorate the latency penalty that comes with multi-socket hardware, and then we investigate the feasibility of applying a distributed log buffer design at the socket level.     

Bandwidth and loss measurements of graded-index microstructured polymer optical fibre

The first bandwidth measurements of graded-index microstructured optical fibres are presented, demonstrating that this novel fibre geometry can provide high-bandwidth multimode polymer fibres without the need for complex doping techniques as with conventional polymer fibres.