This is the first UK national guideline to concentrate on acute lower gastrointestinal bleeding (LGIB) and has been commissioned by the Clinical Services and Standards Committee of the British Society of Gastroenterology (BSG). The Guidelines Development Group consisted of representatives from the BSG Endoscopy Committee, the Association of Coloproctology of Great Britain and Ireland, the British Society of Interventional Radiology, the Royal College of Radiologists, NHS Blood and Transplant and a patient representative. A systematic search of the literature was undertaken and the quality of evidence and grading of recommendations appraised according to the GRADE(Grading of Recommendations Assessment, Development and Evaluation) methodology. These guidelines focus on the diagnosis and management of acute LGIB in adults, including methods of risk assessment and interventions to diagnose and treat bleeding (colonoscopy, computed tomography, mesenteric angiography, endoscopic therapy, embolisation and surgery). Recommendations are included on the management of patients who develop LGIB while receiving anticoagulants (including direct oral anticoagulants) or antiplatelet drugs. The appropriate use of blood transfusion is also discussed, including haemoglobin triggers and targets.

AimThe modified Delphi approach is an established method for reaching a consensus opinion among a group of experts in a particular field. We have used this technique to survey the entire membership of the Association of Coloproctology of Great Britain and Ireland (ACPGBI) to reach a consensus on prioritizing clinical research questions in colorectal disease.MethodThree rounds of surveys were conducted using a web-based tool. In the first, the ACPGBI membership was invited to submit research questions. In Rounds 2 and 3 they were asked to score questions on priority. A steering group analysed the results of each round to identify those questions ranked as being of highest priority.ResultsFive hundred and two questions were submitted in Round 1. Following two rounds of voting and analysis, a list of 25 priority questions was produced, including 15 cancer-related and 10 noncancer-related questions.ConclusionIt is anticipated that these results will: (i) set the research agenda over the next few years for the study of colorectal disease in the United Kingdom, (ii) promote development and (iii) define funding of new research and prioritize areas of unmet clinical need where the potential clinical impact is greatest.

Since the late 1970s, special education in the People's Republic of China has experienced significant reform and fast development. However, education for children with severe developmental disabilities, especially autism spectrum disorders (ASDs), is still the greatest challenge in the field. This paper aims to give readers an overview of what is happening to children with ASDs in China. We first address the issue of prevalence of ASDs, and then offer an introduction to the diagnostic process. After that, a review of disability-related legislation is provided, followed by a description of current treatment options and available educational services. Finally we introduce all extent service providers and their roles.

Metal−organic frameworks (MOFs) are highly ordered, functionally tunable supramolecular materials with the potential to improve dye-sensitized solar cells (DSSCs). Several recent reports have indicated that photocurrent can be generated in Graẗzel-type DSSC devices when MOFs are used as the sensitizer. However, the specific role(s) of the incorporated MOFs and the potential influence of residual MOF precursor species on device performance are unclear. Herein, we describe the assembly and characterization of a simplified DSSC platform in which isolated MOF crystals are used as the sensitizer in a planar device architecture. We selected a pillared porphyrin framework (PPF) as the MOF sensitizer, taking particular care to avoid contamination from light-absorbing MOF precursors. Photovoltaic and electrochemical characterization under simulated 1-sun and wavelength-selective illumination revealed photocurrent generation that is clearly ascribable to the PPF MOF. Continued refinement of highly versatile MOF structure and chemistry holds promise for dramatic improvements in emerging photovoltaic technologies.

Information circulation and availability have always been fundamental to the development of cities even when their employment base depended on manufacturing. With the rise of the informational city, and the global economy, the creation and exchange of highly specialized information has become vital for a metropolitan center's success. This paper, accordingly, examines the contemporary production and exchange of higher‐order information that occurs among and between American cities and reveals how ongoing globalization has affected the position of these cities in the system of information exchange. The paper introduces a conceptual framework combining processes of uncertainty, deregulation, globalization, demassification, and vertical disintegration and deploys that framework in an empirical analysis. An analysis of 1990 flow data provided by Federal Express Corporation measures flows among 47 major U.S. centers and selected foreign places and reveals a three‐tiered hierarchical system, with New York at the top. Domestic information flows are modelled using a competing‐destinations model. The role of population size is paramount and the distance parameter is relatively weak. Centers whose domestic information flows are underestimated by the competing‐destinations model, e.g., New York, Los Angeles, Atlanta, and Dallas, had large absolute volumes of international exports, whereas centers that are overpredicted had lower volumes, e.g., Cleveland, Pittsburgh, Rochester. Using the expansion method, the distance exponent associated with domestic flows of information is found to vary with the level of international information movement in a positive and significant fashion. Command‐and‐control and related producer services have continued to concentrate in select cities throughout the 1980s and to strengthen the hierarchical structure based on information flows. The largest volume of international flows is destined for Europe (Brussels and London), Canada, and Asia (Hong Kong and Tokyo), with New York accounting for 36 percent of all international origins.

A polymerized Si02 particle is made and described, which forms colloidal solutions in water; the particle radius is measured as 500 A by electron microscopy and by dynamic light scatter. The probe ruthenium tris(bipyridyl), Ru(II), immediately associates with the surface of the colloid and shows both spectroscopic and kinetic properties that are indicative of the Si02-water interface. Incubation for several hours leads to a greatly enhanced phosphorescence yield and lifetime for excited Ru(II), while the spectrum shows a marked blue shift with the appearance of two peaks X = 5730 and 6060 A, in comparison to one at X = 6130 A on the Si02 surface. The Ru(II) is bound very tightly to the Si02 particle under these conditions. Solutes such as 02 and nitrobenzene that normally efficiently react with excited Ru(II) are unreactive in this system. However, photoinduced electron transfer occurs between excited Ru(II) and methylviologen, MV2+, giving rise to MV+. The kinetics of electron transfer suggest that an electron tunneling mechanism is operative. The Ru(III) also formed is readily repaired by electron-transfer agents such as ethylenediaminetetraacetic acid (EDTA) and triethanolamine (TEA). The data indicate that Ru(II) is bound tightly and rigidly just below the Si02-water interface. The polymerized Si02 leads to the largest yield of electron transfer or photoexcitation of Ru(II) and MV2+, when compared to water, Nalco silica (surface binding of Ru(II) only), and micellar sodium lauryl sulfate (NaLS).(1) We thank the Army Research Office for support of this work via Grant No. DAAG29-80-K-0007-P001. We also thank the Nalco Chemical Co. for a gift of colloidal silica.

This study uses Federal Express Corporation data t o examine information flows among 48 large metropolitan areas in t h e United States. Set within t h e context of emerging quaternary location theory, three hypotheses are introduced t o explain t h e bases for information flows among metropolitan areas: information genesis, hierarchy of control, and spatial independence. Essential support is found for all three hypotheses. Supply considerations, rather than demand, are fundamental in information genesis; flows are strongly asymmetrical, reflecting a marked hierarchy of control; and distance plays a minor role in the spatial configuration of flows, especially at t h e highest level of t h e metropolitan hierarchy. New York, in particular, dominates t h e national structure of information flows, and only ten metropolitan areas act as command and control centers, creating a highly asymmetric flow in which these ten centers originate a high proportion of total flows. Principal components analysis identified five dominant centers of information genesis: New York, 10s Angeles, Chicago, Atlanta, and Dallas-Ft. Worth. This research extends our understanding of quaternary location in that t h e largest metropolitan areas, containing t h e most specialized and scarce information, a r e most strongly interlocked with o n e another. In addition, t h e spatial extent of information flows and control by a metropolitan area decreases somewhat as t h e level of control of t h e center decreases. As t h e U.S. metropolitan economy continues to become more service and, therefore, more information-oriented, t h e future economic vitality of metropolitan areas is expected to depend o n their position within t h e hierarchy of information control.

No abstract