Perspectives in calorimetry

After a short introduction the situation of electromagnetic and hadronic calorimeters is reviewed. As an outlook important features of future calorimeters are discussed.     

ASHs: application-specific handlers for high-performance messaging

Application-specific safe message handlers (ASHs) are designed to provide applications with hardware-level network performance. ASHs are user-written code fragments that safely and efficiently execute in the kernel in response to message arrival. ASHs can direct message transfers (thereby eliminating copies) and send messages (thereby reducing send-response latency). In addition, the ASH system provides support for dynamic integrated layer processing (thereby eliminating duplicate message traversals) and dynamic protocol composition (thereby supporting modularity). ASHs offer this high degree of flexibility while still providing network performance as good as, or (if they exploit application-specific knowledge) even better than, hard-wired in-kernel implementations. A combination of user-level microbenchmarks and end-to-end system measurements using TCP demonstrates the benefits of the ASH system     

Network morphospace

The structure of complex networks has attracted much attention in recent years. It has been noted that many real-world examples of networked systems share a set of common architectural features. This raises important questions about their origin, for example whether such network attributes reflect common design principles or constraints imposed by selectional forces that have shaped the evolution of network topology. Is it possible to place the many patterns and forms of complex networks into a common space that reveals their relations, and what are the main rules and driving forces that determine which positions in such a space are occupied by systems that have actually evolved? We suggest that these questions can be addressed by combining concepts from two currently relatively unconnected fields. One is theoretical morphology, which has conceptualized the relations between morphological traits defined by mathematical models of biological form. The second is network science, which provides numerous quantitative tools to measure and classify different patterns of local and global network architecture across disparate types of systems. Here, we explore a new theoretical concept that lies at the intersection between both fields, the ‘network morphospace’. Defined by axes that represent specific network traits, each point within such a space represents a location occupied by networks that share a set of common ‘morphological’ characteristics related to aspects of their connectivity. Mapping a network morphospace reveals the extent to which the space is filled by existing networks, thus allowing a distinction between actual and impossible designs and highlighting the generative potential of rules and constraints that pervade the evolution of complex systems.     

Commercial white paint as back surface reflector for thin-film solar cells

In this work, commercially available white paint is applied as a pigmented diffuse reflector (PDR) on the rear surface of thin-film crystalline silicon (c-Si) solar cells with a silicon thickness in the 1–2 μm range. We show that white paint increases the short-circuit current density of the solar cells enormously, with a boost of 41% observed for very thin planar solar cells illuminated with the global AM1.5 solar spectrum. We also show that white paint is a better back surface reflector (BSR) than aluminium, air, a transparent conductive oxide (TCO)/aluminium stack, and even a detached aluminium mirror. While previous studies have investigated the influence of PDRs on silicon solar cells with thicknesses of over 27 μm, this work closes the gap that has existed for much thinner cells.     

Endoscopic fibrin gluing of a pancreatic duct fistula following acute pancreatitis

HISTORY AND CLINICAL FINDINGS: A 45-year-old patient was admitted because of frequent attacks of upper abdominal pain after food intake. The pain episodes had started shortly after a bout of acute pancreatitis. Physical examination was unremarkable except for mild pain on palpation of the left lower abdomen. INVESTIGATIONS: Amylase and gamma-glutamyl transaminase activities as well as inflammatory parameters were slightly raised. Ultrasonography was suggestive of a circumscribed area of necrosis in the tail of the pancreas, a finding confirmed on endoscopic retrograde injection of contrast medium, which passed into the necrotic cavity via a fistula. TREATMENT AND COURSE: The fistula failed to close during 12 days of conservative treatment (total parenteral nutrition; 2 g ceftizoxim twice daily; 1 ampoule somatostatin daily). In three sittings during 6 days, 1-2 ml fibrin glue injections were made by endoscopy retrogradely into the fistular passage resulting in its complete occlusion without any further complications. CONCLUSION: A previously treatment-resistant pancreatic fistula can be successfully occluded by injection of fibrin glue by retrograde endoscopy, obviating surgical intervention with subsequent reduction in glandular capacity.     

The effect of acetazolamide on passive and active transport of fluorescein across the blood-retina barrier in retinitis pigmentosa complicated by macular oedema

BACKGROUND: The carbonic anhydrase inhibitor acetazolamide (AZM) reduces macular oedema in some patients with retinitis pigmentosa. To better understand the oedema-reducing effect of AZM, the effect of AZM on passive permeability and active transport of fluorescein across the blood-retina barrier was studied in patients with retinitis pigmentosa and varying degrees of macular oedema. METHOD: The selection of patients was based on an introductory examination including vitreous fluorometry for qualitative assessment of the vitreous. Macular oedema was graded by fluorescein angiographic leakage. The effect of AZM on the transport properties of the blood-retina barrier was determined by differential spectrofluorometry, in a randomised, double-masked, cross-over study, comprising 2 weeks' treatment with AZM (500 mg/day) and 2 weeks' treatment with placebo. The penetration ratio, defined as the ratio between vitreous concentration 3 mm in front of the retina and the plasma integral, was determined for fluorescein and its metabolite fluorescein glucuronide at 30-60 min and at 120 min after fluorescein injection. Passive permeability and unidirectional permeability in the direction vitreous to blood, due to outward active transport of fluorescein, were determined in those cases where the curves for vitreous concentration of fluorescein could be fitted to a mathematical model. Visual acuity was tested by use of ETDRS standard logarithmic charts. RESULTS: Twenty-two patients volunteered to participate in the study. Signs of significant vitreous detachment/liquefaction caused the exclusion of ten patients after the introductory examination. Nine patients with approximately intact vitreous and varying degrees of oedema completed the cross-over study. AZM treatment was related to a decrease in the penetration ratio of 21% for fluorescein (P=0.01) and of 22% for fluorescein glucuronide (P=0.004). Passive permeability and unidirectional permeability were determined in seven patients. AZM caused a decrease of 27% in the passive permeability of fluorescein (from 1.1 x 10(1) nm/s, P=0.031), and a 95% increase in unidirectional permeability of fluorescein (from 1.2 x 10(2) nm/s, P=0.047). AZM led to a reduction in the grade of macular oedema as determined by fluorescein angiography in three out of seven patients. Only small improvements (< or =5 letters) in visual acuity were noted. CONCLUSION: The present study indicates that the oedema-reducing effect of AZM is due to decreased leakage and stimulated active transport across the blood-retina barrier.     

Sensitivity ofLemna bioassay interacts with stock-culture period

The effect of stock-culture period on the sensitivity of theLemna bioassay to four different phenolic substances was evaluated in this study. The sensitivity of the bioassay interacted with the stock-culture period of either 11, 14, or 18 days. After a seven-day testp-hydroxybenzoic acid (HBA), vanillic acid (VA),trans-cinnamic acid (CA), and ferulic acid (FA) with a concentration of 0.05 mM significantly reduced the number of fronds and the dry weight compared with the untreated control when the stock-culture period had been exactly 14 days. The sensitivity after the shorter (11 days) or longer (18 days) stock-culture period was reduced, and the differences in the dry weight to the untreated control were not significant after a stock culture period of 18 days. The two higher concentrations (0.1 and 0.25 mM) showed stronger inhibition. A comparison of the inhibition at 0.05 mM revealed that the stock-culture period affected the relative toxicity of the four phenolic substances. Since the pH increased in the stock-culture flasks during the 18-day period from 6.25 to 7.9, we hypothesize that differences in theLemna assay can be at least partly attributed to a pH effect, possibly in combination with a relative nutrient deficiency. We recommend a standardization of the stock-culture period to 14 days to improve the sensitivity of theLemna bioassay.