This paper presents the results of a test series to study the vibration behavior of a normal triangular tube bundle subjected to two-phase Freon cross flow. A normal triangular tube bundle of pitch over diameter ratio of 1.5 was tested over a broad range of void fractions and mass fluxes. Fluidelastic instabilities, random turbulence excitation, and damping were investigated. The results were compared with those obtained for a similar tube bundle tested in an air-water cross flow and to those for a rotated triangular bundle similarly tested in Freon.

In September 2007, a meeting entitled ‘Carbohydrate Moieties as Vaccine Candidates’ was held at the National Institutes of Health (Bethesda, MD). This meeting brought together scientists from a number of disciplines to address issues concerning carbohydrate moieties as targets for vaccines for a variety of pathogens and tumors. In addition, the meeting participants addressed fundamental topics of glycoimmunology including the recognition of glycotopes by B and T lymphocytes, the ontogeny of anti-carbohydrate immune responses, peptide mimicry, carbohydrate antigen processing pathways and adjuvants. One session reported progress in the development of new tools such as computational algorithms, glycan arrays and oligosaccharide synthesis and their application to carbohydrate vaccine research. The session titles were: (1) immune response to bacterial carbohydrate antigens; (2) immune response to glycolipids; (3) immune response to carbohydrate antigens on other microbes and on tumors; (4) novel vaccine approaches; (5) novel tools in carbohydrate vaccine research; (6) bench to bedside: carbohydrate moieties as vaccine immunopotentiators.

Background: Since its discovery in 2001 human metapneumovirus (hMPV) has been shown to be a significant cause of human respiratory disease, responsible for 5-8% of respiratory infections in hospitalised children. Diagnosis hitherto has been largely carried out by reverse tanscriptase polymerase chain reaction (RT-PCR) but immunofluorescence staining of cells from nasopharyngeal secretions (IF) offers advantages for some laboratories and may produce a more rapid result in urgent cases. We have recently demonstrated that IF with a rabbit antiserum gave sensitivity equal to that of RT-PCR. However, monoclonal antibodies offer a more plentiful, uniform IF reagent.Objectives: Here we have evaluated a pool of anti-hMPV monoclonal antibodies in the routine diagnosis of respiratory infections in hospitalised infants and children.Study design: Eight hundred and fifty-seven routine respiratory specimens were tested by IF with rabbit polyclonal antiserum and monoclonal antibody pool in parallel. A further 1003 specimens were tested with the monoclonal antibody pool alone. All specimens were also tested for a panel of other respiratory viruses by IF.Results: Both rabbit polyclonal antiserum and monoclonal antibody pool gave positive results in 56 and negative results in 797 specimens. The rabbit polyclonal antibody detected virus in a further two specimens which were negative when tested with the monoclonal pool giving a concordance of 96.6% and a specificity of 100% for the monoclonal antibody pool. Overall hMPV was detected in 5% of specimens whilst 18.4% were positive for hRSV.Conclusions: The monoclonal antibody pool-based IF is a robust assay suitable for routine use with a sensitivity only slightly less than that of the other major diagnostic methodologies available. (C) 2007 Elsevier B.V. All rights reserved.

Chapter 7 Virus Infections in the HSCT Patient C. Taylor, Search for more papers by this authorA. Turner, Search for more papers by this author C. Taylor, Search for more papers by this authorA. Turner, Search for more papers by this author Book Editor(s):Professor Andrew J. Cant, Consultant Paediatric Immunologist, Director of Paediatric Bone Marrow Transplant Unit, Newcastle General Hospital, Newcastle upon TyneSearch for more papers by this authorDr Angela Galloway, Consultant Microbiologist, Royal Victoria Infirmary, Newcastle upon TyneSearch for more papers by this authorDr Graham Jackson, Consultant Haematologist, Director of Adult Bone Marrow Transplant Unit, Royal Victoria Infirmary, Newcastle upon TyneSearch for more papers by this author First published: 01 January 2007 https://doi.org/10.1002/9780470988763.ch7 AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinked InRedditWechat Summary This chapter contains sections titled: Introduction Viruses and diseases Adenoviruses Respiratory viruses Viral gastroenteritis Viruses associated with central system infections Viruses associated with rashes and skin lesions Blood-borne viruses Other viruses — BK Laboratory diagnosis of virus Diagnostic methods according to symptoms Prevention of virus infections Antiviral therapy Developments for the Practical Hematopoietic Stem Cell Transplantation RelatedInformation

Context Polymicrobial diseases, caused by combinations of viruses, bacteria, fungi, and parasites, are being recognised with increasing frequency. In these infections, the presence of one micro-organism generates a niche for other pathogenic micro-organisms to colonise, one micro-organism predisposes the host to colonisation by other micro-organisms, or two or more non-pathogenic micro-organisms together cause disease.Starting point Recently, Gill Regev-Yochay (JAMA 2004; 292: 716-20) and Debby Bogaert (Lancet 2004; 363: 1871-72), and their colleagues, suggested another interaction: microbial interference-the ability of Streptococcus pneumoniae carriage to protect against Staphylococcus aureus carriage, and the inverse effect of pneumococcal conjugate vaccination on the increased carriage of Staph aureus and Staph-aureus-related disease. Strep pneumoniae carriage protected against Staph aureus carriage, and the bacterial interference could be disrupted by vaccinating children with pneumococcal conjugate vaccines that reduced nasopharyngeal carriage of vaccine-type Strep pneumoniae.Where next The medical community is recognising the significance of polymicrobial diseases and the major types of microbial community interactions associated with human health and disease. Many traditional therapies are just starting to take into account the polymicrobial cause of diseases and the repercussions of treatment and prevention.

Carbohydrate epitopes or glycotopes are structurally diverse, occur in a variety of chemical contexts, and are present on the surfaces of cells in the body and on the surfaces of pathogens. These various structures and modes of presentation affect how they are perceived and processed by the body and dictate the outcome of the immune response directed against them. This review focuses on mechanisms of carbohydrate immunity, with an emphasis on carbohydrate vaccines that have been or are being developed for protection against encapsulated bacterial pathogens. We discuss the cellular basis of carbohydrate immunity, newly identified glycotope processing pathways and recognition capabilities, and the synthetic and microarray technologies that are being developed that will permit new experimental approaches to carbohydrate vaccine development and the exploration of the interaction of the immune system with self and nonself glycans.

The dynamic response of U-tubes to two-phase cross-flow has been studied in tests involving a simplified U-tube bundle with a set of flat-bar supports at the apex, subjected to air-water cross-flow over the mid-span region. Tube vibration and the interaction between tubes and supports were measured over a wide range of void fractions and flow rates, for three different tube-to-support clearances. The vibration properties and tube-to-support work-rates could be characterized in terms of the relative influence of fluidelastic instability and random-turbulence excitation. For the first time, in a U-bend tube bundle with liquid or two-phase flow, fluidelastic instability was observed both in the out-of-plane and in the in-plane direction. This raises the possibility of higher-than-expected tube-to-support work-rates for U-tubes restrained by flat bars, particularly if fluidelastic instability, random turbulence and loose supports combine adversely.

`Design guidelines were developed to prevent tube failures due to excessive flow-induced vibration in shell-and-tube heat exchangers. An overview of vibration analysis procedures and recommended design guidelines is presented in this paper. This paper pertains to liquid, gas and two-phase heat exchangers such as nuclear steam generators, reboilers, coolers, service water heat exchangers, condensers, and moisture-separator-reheaters.Generally, a heat exchanger vibration analysis consists of the following steps: (i) flow distribution calculations, (ii) dynamic parameter evaluation (i.e. damping, effective tube mass, and dynamic stiffness), (iii) formulation of vibration excitation mechanisms, (iv) vibration response prediction, and (v) resulting damage assessment (i.e., comparison against allowables). The requirements applicable to each step are outlined in this paper. Part I of this paper covers flow calculations, dynamic parameters and fluidelastic instability. (C) 2003 Elsevier Ltd. All rights reserved.

Design guidelines were developed to prevent tube failures due to excessive flow-induced vibration in shell-and-tube heat exchangers. An overview of vibration analysis procedures and recommended design guidelines is presented in this paper. This paper pertains to liquid, gas and two-phase heat exchangers such as nuclear steam generators, reboilers, coolers, service water heat exchangers, condensers, and moisture-separator-reheaters. Part 2 of this paper covers forced vibration excitation mechanisms, vibration response prediction, resulting damage assessment, and acceptance criteria.

In nuclear power plant steam generators, the vibration response of tubes in two-phase cross-flow is a general concern that in some cases has become a very real long-term wear problem. This paper summarizes the results of the most recent U-bend vibration-response tests in a program designed to address this issue. The tests involved a simplified U-tube bundle with a set of flat-bar supports at the apex, subjected to two-phase air-water cross-flow over the mid-span region of the U-bend. Tube vibration properties and tube-to-support interaction in the form of work-rates were measured over a wide range of flow velocities for homogeneous void fractions from zero to 90%, with three different tube-to-support clearances. The measured vibration properties and work-rates could be characterized by the relative influence of the two most important flow-induced excitation mechanisms at work, fluidelastic instability and random-turbulence excitation. As in previous similar tests, strong effects of fluidelastic instability were observed at zero and 25% void fraction for pitch velocities greater than approximately 0.5 m/s, whereas random turbulence dominated the tube vibration and work-rate response at higher void fractions. In both cases, a link between vibration properties and the effect of the flat-bar supports could be established by comparing the vibration crossing frequency, extracted from time-domain vibration signals, to the participation of the lowest few vibration modes and to the measured work-rate. This approach may be useful when fluidelastic instability, random turbulence and loose supports all combine to result in high work-rates. Such a combination of factors is thought to be responsible for excessive U-tube fretting-wear in certain types of operating steam generators.

The results of a series of tests describing the vibration behavior of several rotated triangular tube bundles subjected to two-phase cross flows are presented. Tube bundles with a pitch-to-diameter ratio of approximately 1.5 were tested over a broad range of void fractions and mass fluxes. Fluidelastic instability, random turbulence excitation, hydrodynamic mass, two-phase damping and local void-fraction were investigated. Well-defined fluidelastic instabilities were observed in continuous two-phase flow regimes. However, intermittent two-phase flow regimes had a dramatic effect on fluidelastic instability leading to lower than expected threshold flow velocities for instability. This effect was more pronounced in Freon two-phase flow than in air-water, and appeared well correlated to the transition between continuous and intermittent flow regimes. Generally, random turbulence excitation forces were much lower in Freon than in air-water. Although very dependent on void fraction, as expected, damping was quite similar in air-water and Freon.

Design guidelines were developed to prevent tube failures due to excessive flow-induced vibration in shell-and-tube heat exchangers. An overview of vibration analysis procedures and recommended design guidelines is presented in this paper. This paper pertains to liquid, gas and two-phase heat exchangers such as nuclear steam generators, reboilers, coolers, service water heat exchangers, condensers. and moisture-separator-reheaters.Generally, a heat exchanger vibration analysis consists of the following steps: 1) flow distribution calculations, 2) dynamic parameter evaluation (i.e. damping, effective tube mass, and dynamic stiffness), 3) formulation of vibration excitation mechanisms, 4) vibration response prediction, and 5) resulting damage assessment (i.e., comparison against allowables), The requirements applicable to each step are outlined in this paper. Part 1 of this paper covers flow calculations, dynamic parameters and fluidelastic instability.

Two-phase cross flow occurs in industrial heat exchangers such as condensers, boilers, and steam generators. Under certain flow regimes and fluid velocities, the fluid forces result in tube vibration and possibly tube damage due to fretting or fatigue. Prediction of these fluid forces requires an understanding of the flow regimes found in heat exchanger tube bundles. Measurements of void fraction within a tube array were taken as an initial step in determining the two-phase flow patterns. The tests were conducted in a Freon 134a test loop at about 1 MPa and 30°C. The measurements were compared against void fraction models commonly used in heat exchanger thermalhydraulic simulation codes and against available flow regime maps. Not surprisingly, the results indicate that a drift-flux model more accurately predicts the void fraction within a tube array. The measurements also confirm the existence of nonuniform void fraction radially around the tube. Based on these measurements and available literature, appropriate void fraction models for use in flow-induced vibration design guidelines are discussed.

Many shell-and-tube heat exchangers operate in two-phase flows. This paper presents the results of a series of experiments done on tube bundles of different geometries subjected to two-phase cross flow simulated by air-water mixtures. Normal (30 deg) and rotated (60 deg) triangular and normal (90 deg) and rotated (45 deg) square tube bundle configurations of pitch-to-diameter ratio of 1.2 to 1.5 were tested over a range of mass fluxes from 0 to 1000 kg/(m(2)s) and void fraction from 0 to 100 percent. The effects of tube bundle geometry on vibration excitation mechanisms such as fluidelastic instability and random turbulence, and on dynamic parameters such as damping and hydrodynamic mass are discussed.

Random excitation forces can cause low-amplitude tube motion that will result in long-term fretting-wear or fatigue. To prevent these tube failures in heat exchangers, designers and troubleshooters must have guidelines that incorporate random or turbulent fluid forces. Experiments designed to measure fluid forces were conducted at the Chalk River Laboratories and at other laboratories worldwide. The data from these experiments were studied and collated, to determine suitable guidelines for random excitation forces. In this paper, a guideline for random excitation forces in single-phase cross flow is presented in the form of normalized spectra that are applicable to a wide range of flow conditions and tube frequencies. In particular, the experimental results used in this study were conducted over the full range of flow conditions found in the liquid region of a nuclear steam generator. The proposed guidelines are applicable to steam generators, condensers, reheaters and other shell-and-tube heat exchangers. They may be used for flow-induced vibration analysis of new or existing components, as input to vibration analysis computer codes and as specifications in procurement documents. [S0094-9930(00)00603-X]

Results of field and laboratory studies provide convincing evidence that micronutrient deficiencies contribute to the mortality and morbidity of infectious diseases. Despite encouraging results in large trials, understanding the mechanisms by which micronutrients contribute to the outcome of the encounter between an individual and an infectious agent requires additional hypothesis-driven research. Presumably, such understanding should lead to translational studies with targeted nutritional therapy. Although these mechanistic studies are varied and complex, they must be done systematically and should include examination of the mechanisms by which micronutrients affect host-pathogen interactions, development of appropriate animal models and reliable methods for the assessment of micronutrient levels, and translation of the results of basic research findings into clinical studies. Moving the frontiers of micronutrient research from the laboratory to the field will be challenging. However, sound scientific research should lead toward better human health.

The reliability of a cytospin-enhanced direct immunofluorescence assay (DFA), using Syva Micro Trak™ monoclonal antibodies, for detection of herpes simplex virus (HSV) was evaluated by comparing results with those of conventional cell culture. Of 250 clinical specimens, 64 were positive for HSV by cell culture, and 22 were positive by cytospin-enhanced DFA, two of which were negative by culture. The sensitivity, specificity, and positive and negative predictive values for cytospin-enhanced DFA were 31.25, 98.9, 90.9, and 80.7%, respectively. Cytospin-enhanced DFA is not an acceptable alternative to cell culture for detection of HSV.

Heat exchanger tubes can be damaged or fail if subjected to excessive flow-induced vibration, either from fatigue or fretting-wear. Good heat exchanger design requires that the designer understands and accounts for the vibration mechanisms that might occur, such as vortex shedding, turbulent excitation or fluidelastic instability. To incorporate these phenomena into a flow-induced vibration analysis of a heat exchanger requires information about damping. Damping in multispan heat exchanger tubes largely consists of three components: viscous damping along the tube, and friction and squeeze-film damping at the supports. Unlike viscous damping, squeeze-film damping and friction damping are poorly understood and difficult to measure. In addition, the effect of temperature-dependent fluid viscosity on tube damping has not been verified. To investigate these problems a single vertical heat exchanger tube with multiple spans was excited by random vibration. Tests were conducted in air and in water at three different temperatures (25, 60 and 90 °C). At room temperature, tests were carried out at five different preloads. Frequency response spectra and resonant peak-fitted damping ratios were calculated for all tests. Energy dissipation rates at the supports and the rate of excitation energy input were also measured. Results indicate that damping does not change over the range of temperatures tested and friction damping is very dependent on preload.

Data from two experimental programs have been analyzed to determine the characteristics of the random excitation forces associated with two-phase cross-flow in tube bundles. Large-scale air-water flow loops in France and Canada were used to generate the data. Tests were carried out on cantilevered, clamped-pinned, and clamped-clamped tubes in normal-square, parallel-triangular, and normal-triangular configurations. Either strain gages or force transducers were used to measure the vibration response of a centrally located tube as the tube array was subjected to a wide range of void fractions and flow rates. Power spectra were analyzed to determine the effect of parameters such as tube diameter, frequency, flow rate, void fraction, and flow regime on the random excitation forces. Normalized expressions for the excitation force power spectra were found to be flow-regime dependent. In the churn flow regime, flow rate and void fraction had very little effect on the magnitude of the excitation forces. In the bubble-plug flow regime, the excitation forces increased rapidly with flow rate and void fraction.