A study of the reactivity of reduced molybdenum ethoxides: Synthesis and characterization of MoO(OH) and some novel molybdenum ethoxide cluster molecules

A low temperature route was used in an attempt to produce reduced molybdenum oxides. When molybdenum (III) ethoxide was hydrolyzed with the stoichiometric amount of water in hydrocarbon solvent, a quantitative yield of product was recovered. Elemental and molybdenum oxidation state analyses on this material indicated an empirical formula of Mo[subscript]2(OH)[subscript]5(OEt). When this material was heated in the presence of hydrogen at 250°C, a black solid was produced. Analyses indicated the material is MoO(OH). All attempts to thermally decompose MoO(OH) to the oxide, Mo[subscript]2O[subscript]3, were unsuccessful. A mixture of Mo[subscript]2O[subscript]3 and MoO[subscript]2 was produced instead. However, MoO(OH) was used, successfully, to synthesize LiMoO[subscript]2 from a reaction with Li[subscript]2CO[subscript]3 at 600°C. In addition, MoO(OH) was also used to synthesize Na[subscript] xMoO[subscript]2 (where x = 0.66);In an attempt to remove the final ethoxide ligand of Mo[subscript]2(OH)[subscript]5(OEt) by reaction with water to produce the pure hydroxide species, Mo(OH)[subscript]3, the hydrolysis reaction was completed using an excess (2-4 molar excess) of water. The solid recovered from this reaction still retained the ethoxide ligand and was slightly oxidized by the excess water. Surprisingly, however, the filtrate of the reaction afforded crystals with the formula, Mo[subscript]6O(OEt)[subscript]18 · 4.8H[subscript]2O. The yield of Mo[subscript]6O(OEt)[subscript]18 was very small. Therefore, attempts were made to synthesize it from reactions of Mo(OEt)[subscript]3 with other oxidizing agents, such as Sb[subscript]2O[subscript]5, C[subscript]6H[subscript]5IO, (CH[subscript]3)[subscript]3NO, and N[subscript]2O. However, these reactions did not successfully produce the cluster;Finally, an alternate synthetic route to isolate reduced molybdenum ethoxides was explored. Mo[subscript]2Cl[subscript]4py[subscript]4 was used in a reaction with sodium ethoxide in neat ethanol. When the reaction was carried out at room temperature overnight, a brown crystalline material was isolated from the ethanol. Elemental analysis of this material suggested the empirical formula could be written as Mo[subscript]4(OEt)[subscript]10py. Single crystal x-ray analysis was not completed due to the highly twinned nature of these crystals;When this reaction was completed in refluxing ethanol, a mixture of homoleptic molybdenum ethoxide species was isolated. Furthermore, a reaction of this molybdenum ethoxide mixture with iodosobenzene produced the novel cluster, Mo[subscript]4(OEt)[subscript]14(HOEt)[subscript]2

The development and psychometric analysis of the conceptual level teacher behavior observation tool

The research literature is replete with information about the teacher shortage. The connection between teacher shortages and teacher classroom effectiveness with student achievement substantiates the need for interventions. Research has identified the potential of developmental mentoring and supervision programs for increasing teacher effectiveness, teacher retention, and student achievement. The purpose of this study was to develop and to analyze the psychometric properties of the Conceptual Level Teacher Behavior Observation Tool (CLTBOT). The purpose of this study was important because the development of the CLTBOT filled a void in the literature for an observation tool that would evaluate teacher behaviors in the conceptual domain. The potential use for these data is tied to mentoring or supervisory practices designed specifically for the teacher’s current need for structure, as well as for showing evidence of growth resulting from program activities. This study was organized into three steps. Step one focused on the development of the CLTBOT. Step two, of this study, explored the validity of the first draft of the CLTBOT in a pilot study. The pilot study indicated a moderate association between an adapted version of Hunt’s Paragraph Completion Method (PCM), the established measure for conceptual development, and the CLTBOT, the focal instrument of this study. The pilot proved an essential step in the process of developing and analyzing the CLTBOT as revisions were made following the results. Step three was the research study designed to answer the research questions. Research question one required an item by item analysis of the CLTBOT. Cohen’s kappa coefficients of between .699 and .867 demonstrated that the two raters’ scores were consistent. Research question two was answered with evaluations of the CLTBOT by two experts who awarded high ratings for the items based on relevance and clarity. A Cramer’s V coefficient of .56 revealed a strong relationship between the CLTBOT and the PCM, establishing evidence for concurrent validity and answering research question three. The results provided preliminary validity and reliability evidence for the use of the Conceptual Level Teacher Behavior Observation Tool (CLTBOT)

Healthcare providers’ perceptions of socioeconomically disadvantaged patients with chronic pain: A qualitative investigation

Socioeconomically disadvantaged individuals are at-risk for chronic pain and disparate care. In this qualitative study, we explored providers’ experiences with socioeconomically disadvantaged patients, with a particular focus on providers’: (1) perceptions of socioeconomically disadvantaged patients’ barriers to pain care, (2) attitudes towards this patient population, and (3) chronic pain decisions for these patients. Individual interviews were conducted with twenty-four healthcare providers. Providers discussed several patient-level access barriers, such as not having health insurance, financial constraints, and scheduling difficulties. Providers believed socioeconomically disadvantaged patients were at-risk to misuse prescription opioids and were less comfortable prescribing opioids to these patients. This investigation found that providers perceived numerous patient-level barriers to pain care, expressed suspicion towards these patients, and considered patients’ socioeconomic status when making pain management decisions. Future investigations should examine the extent to which providers’ attitudes influence their actual pain management decisions and lead to treatment disparities for this patient population

Impact of Race and Sex on Pain Management by Medical Trainees: A Mixed Methods Pilot Study of Decision Making and Awareness of Influence

Objective Previous research suggests female and black patients receive less optimal treatment for their chronic pain compared with male and white patients. Provider-related factors are hypothesized to contribute to unequal treatment, but these factors have not been examined extensively. This mixed methods investigation examined the influence of patients' demographic characteristics on providers' treatment decisions and providers' awareness of these influences on their treatment decisions. Methods Twenty medical trainees made treatment decisions (opioid, antidepressant, physical therapy) for 16 virtual patients with chronic low back pain; patient sex and race were manipulated across patients. Participants then indicated from a provided list the factors that influenced their treatment decisions, including patient demographics. Finally, individual interviews were conducted to discuss the role of patient demographics on providers' clinical decisions. Results Individual regression analyses indicated that 30% of participants were reliably influenced by patient sex and 15% by patient race when making their decisions (P < 0.05 or P < 0.10). Group analyses indicated that white patients received higher antidepressant recommendations, on average, than black patients (P < 0.05). Half of the medical trainees demonstrated awareness of the influence of demographic characteristics on their decision making. Participants, regardless of whether they were influenced by patients' demographics, discussed themes related to patient sex and race; however, participants' discussion of patient demographics in the interviews did not always align with their online study results. Conclusions These findings suggest there is a considerable variability in the extent to which medical trainees are influenced by patient demographics and their awareness of these decision making influences

Immunizations with pneumococcal surface protein A and pneumolysin are protective against pneumonia in a murine model of pulmonary infection with Streptococcus pneumoniae

Intranasal infection of mice with certain strains of capsular group 19 Streptococcus pneumoniae can result in focal pneumonia in the absence of bacteremia. Using this model of murine pneumonia, we demonstrated that immunization with recombinant forms of either pneumococcal surface protein A (PspA) or PdB (a genetically detoxified derivative of pneumolysin) elicited significant protection against focal pulmonary infection. This may be the first demonstration that a proposed vaccine antigen can protect against pneumococcal pneumonia. The best protection was obtained by immunizing mice with a mixture of PspA and PdB, indicating that the protection elicited by these antigens can complement each other. This result is in agreement with previous studies that used pneumococcal sepsis and nasal colonization models and demonstrate that the best protein vaccines for prevention of infection may be those that include more than one protection-eliciting pneumococcal protein.David E. Briles, Susan K. Hollingshead, James C. Paton, Edwin W. Ades, Lea Novak, Frederik W. van Ginkel, and William H. Benjamin, Jr

Immunizations with pneumococcal surface protein A and pneumolysin are protective against pneumonia in a murine model of pulmonary infection with Streptococcus pneumoniae

Intranasal infection of mice with certain strains of capsular group 19 Streptococcus pneumoniae can result in focal pneumonia in the absence of bacteremia. Using this model of murine pneumonia, we demonstrated that immunization with recombinant forms of either pneumococcal surface protein A (PspA) or PdB (a genetically detoxified derivative of pneumolysin) elicited significant protection against focal pulmonary infection. This may be the first demonstration that a proposed vaccine antigen can protect against pneumococcal pneumonia. The best protection was obtained by immunizing mice with a mixture of PspA and PdB, indicating that the protection elicited by these antigens can complement each other. This result is in agreement with previous studies that used pneumococcal sepsis and nasal colonization models and demonstrate that the best protein vaccines for prevention of infection may be those that include more than one protection-eliciting pneumococcal protein.David E. Briles, Susan K. Hollingshead, James C. Paton, Edwin W. Ades, Lea Novak, Frederik W. van Ginkel, and William H. Benjamin, Jr

Pneumococcal surface protein A of invasive Streptococcus pneumoniae isolates from Colombian children.

Pneumococcal surface protein A (PspA) elicits protection in mice against fatal bacteremia and sepsis caused by genetically diverse pneumococci and protects against carriage and lung infection. We determined the PspA families of invasive isolates of Streptococcus pneumoniae recovered from Colombian children <5 years of age. That 97.5% of Colombian isolates belong to PspA families 1 and 2 supports the hypothesis that a human PspA vaccine covering a few PspA families could be broadly effective

Maintenance of the virulence plasmid in Shigella flexneri is influenced by Lon and two functional partitioning systems

Members of the genus Shigella carry a large plasmid, pINV, which is essential for virulence. In Shigella flexneri, pINV harbours three toxin -antitoxin (TA) systems, CcdAB, GmvAT and VapBC that promote vertical transmission of the plasmid. Type II TA systems, such as those on pINV, consist of a toxic protein and protein antitoxin. Selective degradation of the antitoxin by proteases leads to the unopposed action of the toxin once genes encoding a TA system have been lost, such as following failure to inherit a plasmid harbouring a TA system. Here, we investigate the role of proteases in the function of the pINV TA systems and demonstrate that Lon, but not ClpP, is required for their activity during plasmid stability. This provides the first evidence that acetyltransferase family toxin -antitoxin systems, such as GmvAT, can be regulated by Lon. Interestingly, Shigella flexneri pINV also harbours two putative partitioning systems, ParAB and StbAB. We show that both systems are functional for plasmid maintenance although their activity is masked by other systems on pINV . Using a model vector based on the pINV replicon, we observe temperature -dependent differences between the two partitioning systems that contribute to our understanding of the maintenance of virulence in Shigella species

Relationships between drug activity in NCI preclinical in vitro and in vivo models and early clinical trials

An analysis of the activity of compounds tested in pre-clinical in vivo and in vitro assays by the National Cancer Institute's Developmental Therapeutics Program was performed. For 39 agents with both xenograft data and Phase II clinical trials results available, in vivo activity in a particular histology in a tumour model did not closely correlate with activity in the same human cancer histology, casting doubt on the correspondence of the pre-clinical models to clinical results. However, for compounds with in vivo activity in at least one-third of tested xenograft models, there was correlation with ultimate activity in at least some Phase II trials. Thus, an efficient means of predicting activity in vivo models remains desirable for compounds with anti-proliferative activity in vitro. For 564 compounds tested in the hollow fibre assay which were also tested against in vivo tumour models, the likelihood of finding xenograft activity in at least one-third of the in vivo models tested rose with increasing intraperitoneal hollow fibre activity, from 8% for all compounds tested to 20% in agents with evidence of response in more than 6 intraperitoneal fibres (P< 0.0001). Intraperitoneal hollow fibre activity was also found to be a better predictor of xenograft activity than either subcutaneous hollow fibre activity or intraperitoneal plus subcutaneous activity combined. Since hollow fibre activity was a useful indicator of potential in vivo response, correlates with hollow fibre activity were examined for 2304 compounds tested in both the NCI 60 cell line in vitro cancer drug screen and hollow fibre assay. A positive correlation was found for histologic selectivity between in vitro and hollow fibre responses. The most striking correlation was between potency in the 60 cell line screen and hollow fibre activity; 56% of compounds with mean 50% growth inhibition below 10–7.5 M were active in more than 6 intraperitoneal fibres whereas only 4% of compounds with a potency of 10–4 M achieved the same level of hollow fibre activity (P< 0.0001). Structural parameters of the drugs analysed included compound molecular weight and hydrogen-bonding factors, both of which were found to be predictive of hollow fibre activity. © 2001 Cancer Research Campaign www.bjcancer.co