The transition from field emission to collisional space-charge limited current with nonzero initial velocity.

Multiple electron emission mechanisms often contribute in electron devices, motivating theoretical studies characterizing the transitions between them. Previous studies unified thermionic and field emission, defined by the Richardson-Laue-Dushman (RLD) and Fowler-Nordheim (FN) equations, respectively, with the Child-Langmuir (CL) law for vacuum space-charge limited current (SCLC); another study unified FN and CL with the Mott-Gurney (MG) law for collisional SCLC. However, thermionic emission, which introduces a nonzero injection velocity, may also occur in gas, motivating this analysis to unify RLD, FN, CL, and MG.

A randomized study comparing the safety and immunogenicity of a conjugate vaccine combination containing meningococcal group C and pneumococcal capsular polysaccharide--CRM197 with a meningococcal group C conjugate vaccine in healthy infants: challenge phase.

Background: A combination nonavalent pneumococcal-group C meningococcal conjugate vaccine (Pnc9-MenC) was previously found to be safe and immunogenic when administered to infants at 2, 3 and 4 months. This study describes the persistence of immunity at 12 months of age and the immunologic response to a challenge dose of either meningococcal polysaccharide vaccine (Meningivac A+C; MnA+C), or MenC.

Methods: A phase II, randomized, controlled trial of healthy infants.

Reactogenicity of meningococcal C conjugate vaccines when administered at the same time as, or a month prior to or after, tetanus and diphtheria booster vaccinations.

Introduction: This single blind study was conducted to address safety concerns regarding coadministration of diphtheria/ tetanus (DT,Td) boosters and meningococcal C conjugate (MCC) vaccines containing diphtheria or tetanus conjugate proteins.

Methods: 1754 subjects (835 preschoolers and 919 school leavers) were randomised to receive one of three MCC products a month before, after or at the same as routine DT or Td boosters. They (or their parents) completed a health diary for 10 days to record local reactions and systemic symptoms after each vaccination.

Childhood empyema: limited potential impact of 7-valent pneumococcal conjugate vaccine.

During 2003-2004, locally presenting pleural empyema cases in children increased 3-fold. Antigen analysis of empyema fluid identified Streptococcus pneumoniae in 27 of 29 cases for whom samples were available and capsular polysaccharide type 1 in 18 of these. Use of a conjugate vaccine without serotype 1 antigen would have had limited impact on this morbidity in our region.

A survey of time management and particular tasks undertaken by consultant microbiologists in the UK.

Background: Medical microbiology practice encompasses a diverse range of activities. Consultant medical microbiologists (CMMs) attribute widely differing priorities to, and spend differing proportions of time on various components of the job.

Aim: To obtain a professional consensus on what are high-priority and low-priority activities, and to identify the time spent on low-priority activities.

Immunogenicity and boosting after a reduced number of doses of a pneumococcal conjugate vaccine in infants and toddlers.

Background: The minimum number of doses of pneumococcal conjugate vaccine required for protection is not known. We studied the immunogenicity of a reduced schedule in infants and toddlers.

Methods: U.

A randomised controlled study of the reactogenicity of an acellular pertussis-containing pentavalent infant vaccine compared to a quadrivalent whole cell pertussis-containing vaccine and oral poliomyelitis vaccine, when given concurrently with meningococcal group C conjugate vaccine to healthy UK infants at 2, 3 and 4 months of age.

Two hundred forty-one healthy infants were enrolled in an open randomised controlled study of three doses of DTaP-IPV-Hib (Group 1) or DTwP/Hib+OPV (Group 2) at 2, 3 and 4 months of age given concurrently with a meningitis C conjugate vaccine. After each dose, local reactions (any grade) were less common in Group 1 than Group 2 (p<0.03).

Diagnosis of invasive pneumococcal infection by serotype-specific urinary antigen detection.

Widespread use of conjugate pneumococcal polysaccharide-protein vaccines may alter the spectrum of pneumococci producing invasive disease. Novel sensitive diagnostic methods would be valuable for monitoring the epidemiology of pneumococcal disease within populations and vaccine recipients. Ideally, these methods should allow determination of the serotype of the infecting clone.

Immunogenicity and safety of a combination pneumococcal-meningococcal vaccine in infants: a randomized controlled trial.

Context: The success of conjugate vaccines in decreasing invasive disease due to Streptococcus pneumoniae and group C Neisseria meningitidis has placed pressure on crowded infant immunization schedules, making development of combination vaccines a priority.

Objective: To determine the safety and immunogenicity of a combination 9-valent pneumococcal-group C meningococcal conjugate candidate vaccine (Pnc9-MenC) administered as part of the routine UK infant immunization schedule at ages 2, 3, and 4 months.

Design, Setting, And Participants: Phase 2 randomized controlled trial conducted from August 2000 to January 2002 and enrolling 240 healthy infants aged 7 to 11 weeks from 2 UK centers, with home follow-up visits at ages 2, 3, 4, and 5 months.

Immunogenicity of, and immunologic memory to, a reduced primary schedule of meningococcal C-tetanus toxoid conjugate vaccine in infants in the United kingdom.

It has been previously shown that one of the three meningococcal C conjugate (MCC) vaccines introduced in the United Kingdom proved highly immunogenic after the first dose of a three-dose schedule, with evidence of immune memory after dose 3. Thus, in infants a one- or two-dose schedule of this MCC vaccine, conjugated to tetanus toxoid (TT), may suffice. Healthy infants (n = 586) were randomized to receive either one (group 1), two (group 2), or three (group 3) doses of MCC-TT vaccine with a 10- micro g polysaccharide booster given at 13 to 14 months of age.

Rapid diagnosis of bacteremic pneumococcal infections in adults by using the Binax NOW Streptococcus pneumoniae urinary antigen test: a prospective, controlled clinical evaluation.

The diagnosis of severe pneumococcal infections is inadequate, relying heavily on culture of Streptococcus pneumoniae from blood or other normally sterile fluids, and is severely limited by prior administration of antibiotics. We evaluated prospectively the Binax NOW S. pneumoniae urinary antigen test, a rapid immunochromatographic assay, for the diagnosis of bacteremic pneumococcal infections in hospitalized adult patients.

Antibody persistence and immunological memory at age 4 years after meningococcal group C conjugate vaccination in children in the United kingdom.

Antibody persistence and immunological priming for 2 formulations of a meningococcal group C (menC) conjugate (MCC) vaccine (containing 2 or 10 microg of menC polysaccharide) administered at 2, 3, and 4 months of age was investigated by boosting vaccine recipients at age 13-16 months or 4 years with 10 microg of unconjugated menC polysaccharide. At age 4 years, geometric mean titers (GMTs) and concentrations of menC-specific immunoglobulin G and serum bactericidal antibody (SBA) had decreased to prevaccination levels. Geometric mean avidity indices increased after the primary vaccination until age 13-16 months and then remained constant until age 4 years.

Epidemiology of meningococcal disease.

In the UK, serogroup A strains disappeared 50 years ago, but in the 1990s, numbers of cases rose again to a 50-year high. Following the very successful introduction of conjugated meningitis C vaccines, effective meningitis B vaccines are now the highest priority.

Neisseria lactamica protects against experimental meningococcal infection.

Immunological and epidemiological evidence suggests that the development of natural immunity to meningococcal disease results from colonization of the nasopharynx by commensal Neisseria spp., particularly with N. lactamica.

Avidity maturation following vaccination with a meningococcal recombinant hexavalent PorA OMV vaccine in UK infants.

To date, there are no data assessing the utility of avidity indices as a surrogate marker for the induction of immunological memory following meningococcal serogroup B outer membrane vesicle (OMV) vaccination. We studied infants who had been immunized with three doses of a recombinant hexavalent PorA OMV vaccine at ages 2-4 months, together with a fourth dose at age 12-18 months. A control group had received a single dose of the same vaccine at age 12-18 months.

Pneumococcal disease in western Europe: burden of disease, antibiotic resistance and management.

Unlabelled: Streptococcus pneumoniae- the pneumococcus- affects children and adults worldwide. Invasive pneumococcal disease, including pneumonia, meningitis and bacteraemia, has been linked annually to the deaths of millions of children. The pneumococcus is also a significant contributor to mucosal infections such as acute otitis media and sinusitis.