Modified surface-active monomers for adhesive bonding to dentin

PMGDM, a PMDM-type adhesive monomer, was synthesized from pyromellitic dianhydride and glycerol dimethacrylate. Only the para isomer of PMDM, a solid, is used in dental adhesives. The adhesive monomer PMGDM is a liquid and consists of a mixture of para- and meta isomers. This study shows that PMGDM has several advantages over PMDM. For example, the adhesive can be applied at a greater thickness, and additives and/or additional initiators for improved curing can be incorporated. Use of the liquid monomer PMGDM also provided a convenient means of varying the thickness of the adhesive layer between dentin and composite. The adhesive bonds were tested in both shear and tensile modes. PMDM was used as the control. The reliability of the bonds, as judged from the Weibull modulus and Weibull characteristic strength, was improved by (1) use of more concentrated solutions of PMGDM adhesive, (2) use of an adhesive thickness of about 25 microns, and (3) modification of PMGDM with a diluent monomer which is expected to enhance the degree of cure and/or the dentin-wetting properties of the adhesive resin.     

Two cell-wall-associated aminopeptidases from Lactobacillus helveticus and the purification and characterization of APII from strain ITGL1

Lactobacillus helveticus ITGL1 is able to hydrolyse many amino-acyl and dipeptidyl-p-nitroanilides. Analysis of heat inactivation kinetics, metal ion and protease inhibitor effects, and the subcellular location of aminopeptidase activities in both the parental strain and mutants deficient in lysyl-p-nitroanilide hydrolysis, led to the characterization of two cell-wall-associated aminopeptidases, APII and APIV. APII, which catalysed L-lysine p-nitroanilide hydrolysis, was purified about 28-fold to homogeneity from cell-wall extracts of L. helveticus ITGL1 and characterized. The purified enzyme appeared to be monomeric, with a molecular mass of 97 kDa. Aminopeptidase activity was greatest at pH 6.5 and 50 degrees C. APII was completely inhibited by bestatin, chelating agents such as EDTA or 1,10-phenanthroline and the divalent cations Zn2+ and Cu2+. The activity of the EDTA-treated enzyme was restored by Co2+, Ca2+ or Mn2+. Although APII was able to degrade several dipeptides and tripeptides with hydrophobic N-terminal amino acid (Leu, Ala), it was inactive on peptides containing Pro or Gly, and may thus contribute to the development of cheese flavour by processing bitter peptides.     

Analytical formulae for calculating stresses in unidirectional/cross-ply unbalanced laminates

A multilayer theory has been developed for unidirectional/cross-ply unbalanced laminates subjected to surface shear tractions, using the assumption of plane strain. The analytical solution for the stress field in the laminate is obtained and it is shown that the stresses in each layer are in good agreement with the results of a three-dimensional finite element analysis. Approximate formulae for the analytical stresses are also derived for a laminate subjected to an offset distributed force at one end. The accuracy of this solution is shown by comparison with a three-dimensional finite element analysis.     

Serotype-specific amplification of Rickettsia tsutsugamushi DNA by nested polymerase chain reaction

Polymerase chain reaction (PCR) with nested primer pairs was used to diagnose scrub typhus and identify the Rickettsia tsutsugamushi serotype. The primer pairs used for PCR were designed on the basis of the nucleotide sequence of the gene that encodes the 56-kDa antigen. Serotype-specific primers were used in the second PCR amplification. Five serovariants, the Gilliam, Karp, Kato, Kawasaki, and Kuroki strains of R. tsutsugamushi, were identified by nested PCR. In addition, the serotype identified by PCR with DNA from blood clots was the same as that of the strain isolated from five patients with scrub typhus. These findings indicate that this method is useful for diagnosis and identification of the rickettsial serotype in infected patients.     

Enkephalinergic innervation of GABAergic neurons in the dorsal raphe nucleus of the rat

The preembedding double immunoreaction method was used to study interrelations of enkephalinergic and GABAergic neuronal elements in the dorsal raphe nucleus of the Wistar albino rat. The enkephalin-like neuronal elements were immunoreacted by the peroxidase-antiperoxidase method and silver-gold intensified, which showed strongly and was specific. The GABA-like immunoreactive neurons were immunoreacted by the peroxidase-antiperoxidase method only. GABA-like neural somata were postsynaptic to both the enkephalin-like immunoreactive and the non-immunoreactive axon terminals. The enkephalin-like immunoreactive axon terminals were also found to synapse GABA-like immunoreactive dendrites. The GABA-like immunoreactive neuronal elements were also found to receive synapses from other non-immunoreactive as well as GABA-like immunoreactive axon terminals. Almost all of the synapses appeared to be asymmetrical. Possible functional activity of interactions among the enkephalinergic, GABAergic, and serotonergic neuronal elements in the dorsal raphe nucleus are discussed.     

Holocaust survivors and escapees: Their strengths.

The conclusions clinicians have drawn about Holocaust survivors over the last 50 yrs differ sharply from researchers' findings. It is important to evaluate these discrepancies since different perceptions of survivors affect treatment approaches. The researchers' view, stressing the survivor's resilience and resourcefulness, contrasts with clinical impressions centering on a survivor syndrome involving deep emotional disturbances as residues of the Holocaust experience. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A coverage plan for health centres in Murewa district in Zimbabwe: an example of action research

Good access to health facilities providing good first-level health care remains problematic in many developing countries. It is a hindrance to effective and efficient functioning of the hospital, as outpatient departments become overcrowded with patients from areas without health centres. In many cases the quality of care delivered to these patients is poor because within the district health system the hospital is not the best place for the supply of comprehensive, integrated and continuous care. Eventually, high hospital involvement in first-level care can jeopardize the delivery of adequate referral care for those patients who desperately need the hospital's technology and expertise. This paper provides an account of the way this problem was investigated and managed by the district health management team in the Murewa district in north-east Zimbabwe. The design of a comprehensive 'master plan' or 'coverage plan' is presented as well as the problems and difficulties encountered. The Murewa experience highlights the relevance of a coverage plan for rational and coherent health infrastructure planning at district level. The approach followed by the Murewa team illustrates the use of action research as an integral part of the management of district health systems.     

Risk-based recommendations for mammographic screening for women in their forties

PURPOSE: To develop risk-based recommendations for mammographic screening for women in their 40s that take into account the woman's age, race, and specific risk factors. METHODS: We assumed that regular mammographic screening is justified for a 50-year-old woman, even one with no risk factors, and that a younger woman with an expected 1-year breast cancer incidence rate as great or greater than that of a 50-year-old woman with no risk factors would benefit sufficiently to justify regular screening. Recommendations under this criterion were based on age- and race-specific breast cancer incidence rates from the National Cancer Institute's (NCI's) Surveillance, Epidemiology, and End Results (SEER) Program; assessments of risk factors from the Breast Cancer Detection and Demonstration Project (BCDDP); and reports in the literature. RESULTS: Two methods, the exact-age procedure (EAP) and the grouped-age procedure (GAP), were developed. The less precise GAP only requires following a flow diagram. The proportion of white women recommended for screening by the EAP ranges from 10% for 40-year-old women to 95% for 49-year-old women, and the corresponding percentages for black women are 16% and 95%. The assumptions that underlie the guidelines are discussed critically. CONCLUSION: For women or physicians who prefer an individualized approach in deciding whether to initiate regular mammographic screening in the age range of 40 to 49 years, the present report offers recommendations based on individualized risk-factor data and clearly stated assumptions that have an empiric basis. These recommendations can be used to facilitate the counseling process.