A longitudinal study of Salmonella and Campylobacter jejuni isolates from day of hatch through processing by automated ribotyping

Comparisons of bacterial populations over long periods of time allow researchers to identify clonal populations, perhaps those responsible for contamination of farms or humans. Salmonella and Campylobacter can cause human illness, and our objective was to use a library typing system to track strains that persist in the poultry house and through the processing plant. Two farms, over four consecutive flocks, were studied. Multiple samples were taken of the poultry house environment, feed mill, transport crates, and carcasses in the processing plant. Sample collection on the farm took place on chick placement day, midgrowout, and the day of harvest. This study found that 80.3% of isolates belonged to a single strain of Salmonella Kentucky that persisted in several environmental samples for all flocks at both farms, from chick placement day to the final product at the plant. Surgical shoe covers produced most isolates (n = 26), and processing day yielded the highest recovery (n = 68). Additional serotypes were recovered, but the Salmonella Kentucky-positive eggshells and chick mortality appeared to be the source of the organism for both farms. All Campylobacter isolates recovered were identified as C. jejuni. Most Campylobacter isolates (90.1%) belonged to one of three core strains. C. jejuni was not recovered on chick placement day. Cecal droppings yielded all nine strains. Most isolates (98.2%) were from one farm. Cluster analysis grouped C. jejuni and Salmonella isolates into four and six distinct clusters, respectively, on the basis of a similarity level of 80%.     

Brewer's asthma due to malt contamination

We describe a case of a 28 year old brewery worker who developed asthma whilst grinding malt. Lung function measurements demonstrated deterioration and improvement in lung function associated with work and absence from work. Inhalation challenge with ground malt from the brewery was positive but with ground malt from another source was negative suggesting a contaminant of the malt was responsible. Culture of the brewery malt showed heavy contamination with Aspergillus niger, but A. niger skin test was negative and aspergillus-specific IgG was not detected in the patients serum. Removal of the subject from the grinding room resulted in resolution of symptoms and normal lung function. We discuss the role of A. niger as an aetiological agent for occupational asthma with reference to the above case.     

Micro-truss nanocrystalline Ni hybrids

A low-density nanocrystalline material was created by electroforming nanocrystalline Ni around a rapid prototyped acrylic photopolymer micro-truss. This new hybrid material combines the structural efficiency of micro-truss architectures with the ultra-high strength that can be achieved by grain size reduction to the nanometer scale. A range of strut thicknesses were electrodeposited and tested in uniaxial compression. Strut failure occurred by inelastic buckling in the core (compression) members and tensile fracture in the face-sheet (tension) members. Experimental knockdown factors were determined from the idealized compressive modulus and peak strength models and used to map the optimal strut geometry in terms of deposited Ni and the initial strut cross-section.     

Bibliography of literature on medical equipment reliability

This paper presents a brief introduction and an extensive list of selective references on medical equipment reliability.     

Thiophene hydrodesulfurization over bimetallic and promoted nitride catalysts

Alumina-supported bimetallic (Co₃Mo₃N/Al₂O₃” and promoted (Co–Mo₂N/Al₂O₃) nitride catalysts have been prepared and characterized. Thiophene hydrodesulfurization (HDS) measurements show that the Co₃Mo₃N/Al₂O₃ and Co–Mo₂N/Al₂O₃ catalysts are significantly more active than a Mo₂N/Al₂O₃) catalyst with the same Mo loading. Furthermore, the Co–Mo₂N/Al₂O₃ catalyst has a substantially higher HDS activity than a sulfided Co–MoO₃/Al₂O₃ catalyst with an identical metal loading. This revised version was published online in July 2006 with corrections to the Cover Date.     

Hydrogen‐bond acidic polyhedral oligosilsesquioxane filled polymer coatings for surface acoustic wave sensors

A series of novel polyhedral oligosilsesquioxane nanofiller compounds functionalized with hydrogen‐bond acidic sensor groups was prepared, characterized by IR, ¹H‐, ¹³C‐ and ²⁹Si‐NMR, and MALDI‐TOF MS, and formulated into polymer coatings for 500 MHz surface acoustic wave sensor platforms. Sensor responses to the explosives simulant dinitrotoluene and to the nerve agent simulant dimethyl methylphosphonate were studied, and the performances of the polyhedral oligosilsesquioxane formulations were compared with those of conventional hydrogen‐bond acidic linear surface acoustic wave sensor polymers carrying the same sensor groups. The polyhedral oligosilsesquioxane formulations gave good initial responses to the simulants, maintained 40–65% of their original response over a period of 6 months and maintained their sensitivity down to a simulant vapor concentration of 1 ppb v. The surface compositions of the surface acoustic wave sensor coatings were characterized by sum frequency generation spectroscopy. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Morphometric quantification of atherosclerotic plaques by computer-assisted image-analysis of histographs

A method is described for quantifying the amount of atherosclerotic plaque in collapsible blood vessels by a computer-assisted image analysis of cross-sectional contours traced under microscopic visualization. The digitized contours are processed using a computer program that transforms the irregular image of the collapsed vessel into an ideal geometry and then calculates in vivo linear and areal parameters, variables, and ratios. The analysis is based on conventional stereologic principles and utilizes relatively inexpensive and widely available equipment: microscope with drawing tube attachment, digitizing board, microcomputer, monitor, and printer or plotter. Some of the output data include the fraction of vessel lumen occluded by plaque, average thickness of plaque, the fraction of wall surface area covered by plaque, and the ratio of the vessel bore to vessel wall volumes. The error and precision of measuring lumen occlusion and plaque surface area are assessed.     

Overexpression of cadherins and underexpression of beta-catenin inhibit dorsal mesoderm induction in early Xenopus embryos

The cadherin-catenin complex has an important role in cell-cell adhesion and may also function in signaling pathways. We report that overexpression of three cadherin types in Xenopus embryos causes them to develop with reduced dorsal axial structures. The same phenotype is produced in embryos that have been depleted of maternal beta-catenin protein by an antisense oligodeoxynucleotide complementary to beta-catenin mRNA. They show an inhibition in the expression of dorsal mesodermal markers MyoD and goosecoid, but not of ventral and general mesodermal markers. They lack notochords, somites, and neural tubes and are defective in dorsal mesodermal signaling in Nieuwkoop assays. The phenotype can be rescued by the injection of beta-catenin mRNA and not by the injection of Xwnt-8 mRNA. These results show that beta-catenin has an important role in dorsal mesoderm induction. They directly demonstrate the activity of a maternal mRNA in axis specification.     

Standardized assessment of concussion (SAC): on-site mental status evaluation of the athlete

OBJECTIVE: This study investigated the clinical utility of the Standardized Assessment of Concussion (SAC) in detecting concussion in athletes. METHOD: Athletic trainers administered the SAC to 568 nonconcussed high school and college football players prior to the 1995 and 1996 football seasons. Thirty-three of these players experienced concussion and were tested immediately following injury; 28 of the 33 underwent additional follow-up testing 48 hours after the injury. RESULTS: Concussed players scored significantly below nonconcussed controls on all SAC measures and significantly below their own pre-injury baseline performance. Follow-up testing documented return to preinjury baseline. CONCLUSION: These findings support the SAC's effectiveness in detecting concussion and tracking recovery in order to determine a player's fitness to return to play.     

Immunologic and structural relationships of the minor pilus subunits among Haemophilus influenzae isolates

Two proteins, HifD and HifE, have been identified as structural components of Haemophilus influenzae pili. Both are localized at the pilus tip, and HifE appears to mediate pilus adherence to host cells. In this study we examined the immunologic and structural diversity of these pilus subunits among type b H. influenzae (Hib) and nontypeable H. influenzae (NTHI) strains. Western immunoblot analysis revealed that antibodies directed against the C terminus of HifD and HifE from Hib strain Eagan bound to HifD and HifE proteins, respectively, of all piliated Hib and NTHI strains tested. Whole-cell enzyme-linked immunosorbent assays showed that antibodies specific for native HifD or HifE of strain Eagan also bound to all piliated Hib strains but did not bind to the piliated NTHI strains. Antibodies against HifE of strain Eagan inhibited the binding of Hib to human erythrocytes but did not inhibit the binding of NTHI strains. Restriction fragment length polymorphism (RFLP) analysis was used to determine strain-to-strain structural differences within hifD and hifE genes, either by PCR or by nucleotide sequence analysis. DNA and derived amino acid sequence analyses of HifD and HifE confirmed the uniqueness of the RFLP types. The hifD and hifE genes of all type b strains showed identical restriction patterns. Analysis of hifD and hifE genes from the NTHI strains, however, revealed seven unique RFLP patterns, suggesting that these genes encode proteins with diverse primary structures. These results indicate that HifD and HifE are immunologically and structurally similar among the Hib strains but vary among the NTHI strains.