Microbial Decontamination and Weight of Carcass Beef as Affected by Automated Washing Pressure and Length of Time of Spray

Carcass beef has traditionally been washed by hand to remove foreign material such as hair, soil particles, and microbiological organisms that have contaminated the surfaces. These carcasses are inspected by the Food Safety Inspection Service (FSIS)to detect defects related to carcass cleanliness. Recent research and development of technology have emphasized automated machine washing. At pressures above that normally used, it is conceivable that water could penetrate tissue surfaces and be absorbed by the carcasses. Also, longer wash periods may enhance water uptake by carcasses. According to the ASH RAE Handbook and Product Directory, the average shrinkage of carcass beef using good current practices was 1.3% at 20 hr postmortem. USDA meat inspection regulations required that carcasses sustain no net increase in weight due to absorption of water during the washing process. There is no available literature on the effects of various automated washing techniques on carcass weights after a 20-hr chill. The objectives of the study reported presently were to determine the effects of nozzle pressure and length of time washed on the microflora and weights of carcass beef at 20 hr postmortem

The newly developed CRF1-receptor antagonists, NGD 98-2 and NGD 9002, suppress acute stress-induced stimulation of colonic motor function and visceral hypersensitivity in rats.

Corticotropin releasing factor receptor 1 (CRF1) is the key receptor that mediates stress-related body responses. However to date there are no CRF1 antagonists that have shown clinical efficacy in stress-related diseases. We investigated the inhibitory effects of a new generation, topology 2 selective CRF1 antagonists, NGD 98-2 and NGD 9002 on exogenous and endogenous CRF-induced stimulation of colonic function and visceral hypersensitivity to colorectal distension (CRD) in conscious rats. CRF1 antagonists or vehicle were administered orogastrically (og) or subcutaneously (sc) before either intracerebroventricular (icv) or intraperitoneal (ip) injection of CRF (10 µg/kg), exposure to water avoidance stress (WAS, 60 min) or repeated CRD (60 mmHg twice, 10 min on/off at a 30 min interval). Fecal pellet output (FPO), diarrhea and visceromotor responses were monitored. In vehicle (og)-pretreated rats, icv CRF stimulated FPO and induced diarrhea in >50% of rats. NGD 98-2 or NGD 9002 (3, 10 and 30 mg/kg, og) reduced the CRF-induced FPO response with an inhibitory IC50 of 15.7 and 4.3 mg/kg respectively. At the highest dose, og NGD 98-2 or NGD 9002 blocked icv CRF-induced FPO by 67-87% and decreased WAS-induced-FPO by 23-53%. When administered sc, NGD 98-2 or NGD 9002 (30 mg/kg) inhibited icv and ip CRF-induced-FPO. The antagonists also prevented the development of nociceptive hyper-responsivity to repeated CRD. These data demonstrate that topology 2 CRF1 antagonists, NGD 98-2 and NGD 9002, administered orally, prevented icv CRF-induced colonic secretomotor stimulation, reduced acute WAS-induced defecation and blocked the induction of visceral sensitization to repeated CRD

Cascading effects of a highly specialized beech-aphid–fungus interaction on forest regeneration

Specialist herbivores are thought to often enhance or maintain plant diversity within ecosystems, because they prevent their host species from becoming competitively dominant. In contrast, specialist herbivores are not generally expected to have negative impacts on non-hosts. However, we describe a cascade of indirect interactions whereby a specialist sooty mold (Scorias spongiosa) colonizes the honeydew from a specialist beech aphid (Grylloprociphilus imbricator), ultimately decreasing the survival of seedlings beneath American beech trees (Fagus grandifolia). A common garden experiment indicated that this mortality resulted from moldy honeydew impairing leaf function rather than from chemical or microbial changes to the soil. In addition, aphids consistently and repeatedly colonized the same large beech trees, suggesting that seedling-depauperate islands may form beneath these trees. Thus this highly specialized three-way beech-aphid–fungus interaction has the potential to negatively impact local forest regeneration via a cascade of indirect effects

SHARED TEAM EXPERIENCES AND TEAM EFFECTIVENESS: UNPACKING THE CONTINGENT EFFECTS OF ENTRAINED RHYTHMS AND TASK CHARACTERISTICS

This study explores the conditions under which shared team task-specific (STTS) experiences in crew-based arrangements may negatively influence team effectiveness.We suggest that the entrained rhythms featured in social entrainment theory act as a dual-edged sword with the potential to generate complacency detriments in addition to the commonly cited synchronization benefits. We argue that the manifestation and influence of the countervailing forces (i.e., synchronization and complacency) on the STTS experience—team effectiveness relationship will depend on salient task characteristics (i.e., frequency and difficulty). More specifically, frequently performed tasks create conditions for complacency tomanifest (generating an inverted-U shaped relationship between STTS experience—team efficiency), whereas infrequently performed tasks do not (generating a positive, linear relationship). We further this distinction by layering on task difficulty that, we posit, acts to amplify the respective negative and positive consequences. Analyses of archival data from 8,236 surgeries performed over one year at a large hospital located in the southwestern region of the United States were consistent with our hypotheses and 30 semi-structured interviews with operating room personnel added richness and precision to our theory. Ancillary analyses on patient post-surgery recovery rate yielded additional insights. Implications and future directions are discussed

SHARED TEAM EXPERIENCES AND TEAM EFFECTIVENESS: UNPACKING THE CONTINGENT EFFECTS OF ENTRAINED RHYTHMS AND TASK CHARACTERISTICS

This study explores the conditions under which shared team task-specific (STTS) experiences in crew-based arrangements may negatively influence team effectiveness.We suggest that the entrained rhythms featured in social entrainment theory act as a dual-edged sword with the potential to generate complacency detriments in addition to the commonly cited synchronization benefits. We argue that the manifestation and influence of the countervailing forces (i.e., synchronization and complacency) on the STTS experience—team effectiveness relationship will depend on salient task characteristics (i.e., frequency and difficulty). More specifically, frequently performed tasks create conditions for complacency tomanifest (generating an inverted-U shaped relationship between STTS experience—team efficiency), whereas infrequently performed tasks do not (generating a positive, linear relationship). We further this distinction by layering on task difficulty that, we posit, acts to amplify the respective negative and positive consequences. Analyses of archival data from 8,236 surgeries performed over one year at a large hospital located in the southwestern region of the United States were consistent with our hypotheses and 30 semi-structured interviews with operating room personnel added richness and precision to our theory. Ancillary analyses on patient post-surgery recovery rate yielded additional insights. Implications and future directions are discussed

Chemical Reaction Dynamics at Surfaces

Contains reports on six research projects.Joint Services Electronics Program Contract DAAL03-89-C-0001MIT Energy Laboratory - Synthetic Fuels CenterNational Science Foundation Grant CHE 85-08734Petroleum Research Fund Contract 19014-AC

Role of interspecies transfer of chromosomal genes in the evolution of penicillin resistance in pathogenic and commensal Neisseria species

The two pathogenic species of Neisseria, N. meningitidis and N. gonorrhoeae , have evolved resistance to penicillin by alterations in chromosomal genes encoding the high molecular weight penicillin-binding proteins, or PBPs. The PBP 2 gene ( penA ) has been sequenced from over 20 Neisseria isolates, including susceptible and resistant strains of the two pathogenic species, and five human commensal species. The genes from penicillin-susceptible strains of N. meningitidis and N. gonorrhoeae are very uniform, whereas those from penicillin-resistant strains consist of a mosaic of regions resembling those in susceptible strains of the same species, interspersed with regions resembling those in one, or in some cases, two of the commensal species. The mosaic structure is interpreted as having arisen from the horizontal transfer, by genetic transformation, of blocks of DNA, usually of a few hundred base pairs. The commensal species identified as donors in these interspecies recombinational events ( N. flavescens and N. cinerea ) are intrinsically more resistant to penicillin than typical isolates of the pathogenic species. Transformation has apparently provided N. meningitidis and N. gonorrhoeae with a mechanism by which they can obtain increased resistance to penicillin by replacing their penA genes (or the relevant parts of them) with the penA genes of related species that fortuitously produce forms of PBP 2 that are less susceptible to inhibition by the antibiotic. The ends of the diverged blocks of DNA in the penA genes of different penicillin-resistant strains are located at the same position more often than would be the case if they represent independent crossovers at random points along the gene. Some of these common crossover points may represent common ancestry, but reasons are given for thinking that some may represent independent events occurring at recombinational hotspots.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/48045/1/239_2004_Article_BF00182388.pd

Anion‐π catalysis enabled by the mechanical bond

We report a series of rotaxane-based anion–π catalysts in which the mechanical bond between a bipyridine macrocycle and an axle containing an NDI unit is intrinsic to the activity observed, including a [3]rotaxane that catalyses an otherwise disfavoured Michael addition in >60 fold selectivity over a competing decarboxylation pathway that dominates under Brønsted base conditions. The results are rationalized by detailed experimental investigations, electrochemical and computational analysis