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Cost analysis of the University of Wisconsin-Stout unclassified recruitment and selection processLeCompte, Angela D. January 2003 (has links) (PDF)
Thesis--PlanB (M.S.)--University of Wisconsin--Stout, 2003. / Includes bibliographical references.
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Publications of the Faculty and Staff, College of AgricultureAgricultural Experiment Station, College of Agriculture. University of Arizona., Cooperative Extension Service, College of Agriculture. University of Arizona. January 1970 (has links)
No publication date on item. / Publications of the Faculty and Staff, College of Agriculture (From July 1, 1969 to June 30, 1970) / Series P-18.
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Faculty, Technology, and the Community College: Faculty Culture and Cyber CultureSmith-Hawkins, Paula L January 2005 (has links)
A qualitative study of faculty work and technology was used to identify four areas of change to community college faculty work structures; specifically, time, work space, classroom teaching and faculty service work. By examining the policies, programs, and technology initiatives as negotiated by faculty members---their work, their interactions with students, other faculty, administrators, and the local community this writer argues that technology has destabilized the nature of faculty work and the structures once associated with faculty responsibilities. This ethnography relies heavily on the theories of Rhoades, Burris, Perlow, and Vallas to examine how technology has changed the daily work of the community college faculty member.Using the ethnographic approach to qualitative research, the data for this study comes from meetings, formal and informal exchanges, writings, and promotional material handed to faculty over a two year periods. The participant/observer approach utilized in this study allows for insight into the complicated relationships between policies and practices, and formal and informal interactions between various campus groups. This particular campus site struggled with the new policies governing informational and educational technology decisions in a setting that promoted a high degree of faculty input and participation. The information gathered in this study points to the destabilizing nature of technology on faculty work.
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CLINICALLY RELEVANT EX VIVO FATTY ACID PROFILES FROM A LIPID MODEL FOR COLORECTAL ADENOCARCINOMANel, Amanda 23 October 2009 (has links)
The challenge we face today is identification of the mechanisms
through which dietary factors perturb fundamental fatty acid (FA) pathways in cancer cells.
In principle, insight into a lipid model for the cancer entity under assessment is required.
This prompted and investigation into FA role-players that drive cellular over-production
and apoptotic pathways under circumstances where environmental factors impede
essential fatty acid metabolism (EFAM) that contributes to colorectal cancer (CRC).
Ultimately, better understanding of FA metabolic pathways followed under colorectal
pathological conditions can contribute to improved therapies by which growth and
recurrence of this disease may be obviated. PURPOSE OF STUDY: The primary goal of
this study was to construct clinically relevant ex vivo FA profiles from a lipid model for
colorectal adenocarcinoma, not previously reported in the literature. Aims were to identify
prominent FA role-players and to debate their involvement in different signaling pathways.
The final purpose of this study was to present a rationale for adjuvant FA therapies to
improve the management of CRC. MATERIAL AND METHODS: The study group
consisted of CRC biopsies (TNM staging, mostly T2/T3) and normal colorectal mucosal
biopsies, (n8 of each group). Biopsy selection was hampered by difficult circumstances,
since most patients received treatment prior to surgery. All the lipid analyses were
personally conducted at the Biolipid Division of the Department Biochemistry at the
University of the Free State (UFS) as follows: lipids were extracted; total lipids (TLs) were
fractionated into neutral lipids (NLs) and phospholipids (PLs); phosholipid subclasses, i.e.
phosphatidylcholine, (PC), phosphatidylserine (PS), phosphatidylethanolamine (PE) and
phosphatidylinositol (PI), were separated; and fatty acid methyl esters of all the classes
and subclasses were analyzed. Lipid analyses were done according to well established
and internationally accepted gaschromatography (GLC) and thin layer chromatography
(TLC) techniques. Statistical analyses were performed by a biostatistician attached to the
UFS, and p-values and 95% confident intervals (95% CI) for median of differences, as
well as specific ratios were calculated. MAIN RESULTS AND DISCUSSION: The ex vivo
phospholipid FA profile for CRC cells revealed linoleic acid (LA), arachidonic acid (AA),
palmitic acid (PA) and oleic acid (OA) as main role-players involved in CRC. An extensive
literature study revealed that: prolonged inflammatory responses and oxidative events,
marked by the up-regulation of cyclooxygenases (COXs) and inducible nitric oxide
synthase (iNOS), contribute to colorectal carcinogenesis; and prolonged cytokine mediated responses, orchestrated by nuclear factor-kappa Beta (NF-κβ) with consequent
immunodeficiency, are prevalent in CRC patients. Past research revealed without doubt
that high dietary AA intake (meat) and COX-2 metabolism play a pivotal role during
colorectal carcinogenesis. CRC is a stress-related cancer and it is plausible that high iron
intake and lipids contribute to chronic inflammation and radical-mediated cell damage in
this age-related disease. Current research directions in CRC concern LOX metabolism
and peroxisome proliferator activator receptors (PPARs) are receiving much attention,
especially PPARδ/β that was an enigma and elicited controversial debate in adenomas
(polyps) and adenocarcinoma. Taken together at this point in time, the impact of
environmental factors on essential fatty acid metabolism (EFAM) that impede LA
conversion to AA via delta-6 and -5 desaturase (Î6d and Î5d) pathways with up-regulation
of the fatty acid synthase (FAS) and Î9d pathways, and the down-regulation of LA
oxidative metabolism via the 15 LOX-1 pathway with up-regulation of the COX-2 and 15-
LOX-2 pathways of AA, is characteristic of colorectal carcinogenesis. Seen in context, the
lipid findings of this study integrated with evidence-based information in the literature
encompasses the following: excessive dietary linoleic acid (LA) intake that can contribute
to cell proliferation, radical-mediated cell damage, and the production of conjugated
linoleic acid (CLA) in the gut; high dietary AA intake and COX-2 over-expression that play
a pivotal role during carcinogenesis and immune responses with consequent exhaustion
of the AA source; enhanced FAS and Î9d activities that contribute to, respectively,
enhanced palmitic acid (PA) and oleic acid (OA), is prevalent in CRC cells. The high PA
content in CRC cells apparently activates PPARδ/β and thereby suppresses apoptosis, a
crucial factor in the pathobiology of CRC. The link between OA and CRC still needs
proper clarification. It is conceivable that the high saturated fatty acid (SFA) content
observed in CRC cells, exogenous intake with red meat and endogenous production by
enhanced FAS activity, contribute to colorectal carcinogenesis and immunodeficiency in
CRC patients, since it can stimulate COX-2 expression (and PGE2 activity) and downregulate
the Th1 immune pathway that make CRC a Th2 dominant disease. Taken in
consideration that lipid rafts rich in SFAs down-regulate the Th1 cytokine subset,
particularly interleukin-2 (IL-2) that stimulates lymphocyte production, it is plausible that
management of the CRC patient is hampered by immunodeficiency. All the altered cell
signaling pathways in CRC debated in this study served as sound foundation for clinical
intervention with adjuvant FA therapeutic strategies to improve CRC management.
CONCLUSION: The identification of prominent FA role-players in CRC cells that serve as
ligands for specific PPAR family members contributed to the assessment of FA driven
proliferation and apoptotic pathways characteristic of CRC. It is conceivable that enhanced PA (and LA) contributes to PPARδ/β over-expression that can suppress PPARγ
(and PPARα) activity and then tilts the scale in favor of apoptotic resistance and survival
of CRC cells. From an epidemiological viewpoint, excessive iron and SFAs seem to be
important co-factors in the multifactorial etiology of CRC. The biohydroxygenation of LA
to different CLA products in the gut and to what extent harmful CLA products may pose a
danger need to be fully explored, especially since the uptake of beneficial products is
apparently limited. Among current therapeutic options in the field of lipids, concurrent
therapy with a COX-2 inhibitor (Celecoxib) and docosahexaenoic acid (DHA) to improve
membrane fluidity and the impact of drug therapy entered clinical trials and although the
outcome is still awaited, the impact of DHA on lymphocyte production may be a concern.
Based on a mountain of evidence presented in this study, it is suffice to say that there is a
rationale for additional adjuvant FA therapies that can be included in the existing
therapeutic regime for CRC management. Firstly, CLA and EPA therapy for prevention of
polyp recurrence and improvement of immunocompetence in CRC patients and secondly,
GLA and EPA therapy in the management of patients with a history of polyp growths is
proposed.
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THE EVALUATION OF STRATEGIES FOR PRODUCING OPTIMAL INHALANT THERAPY IN PRESCHOOL CHILDREN (2-6 YEARS) WITH CHRONIC ASTHMASchultz, André 15 December 2010 (has links)
Background:
The dose of inhaled medication reaching a patient is dependent on drug formulation,
method of delivery, output and correct use of the delivery device and frequency of use.
The most commonly used aerosol drug delivery device in preschool children is the
pressurised metered-dose inhaler (pMDI) -spacer. This study evaluated strategies for
improving the delivery of inhalation therapy in preschool children by focusing on factors
affecting the optimal use of pMDI-spacers and on the frequency of their use as determined
by adherence to prescribed drug regimes.
The study was divided into two parts. Part 1 examined the number and type of breaths
needed for efficient drug delivery through a pMDI-spacer in preschool children. Part 2 was
a randomised, controlled, prospective clinical trial in which a comparison was made
between an incentive spacer device and a small volume spacer with respect to adherence,
correct device use (spacer technique) and clinical outcome.
Overall aims:
⢠To determine how many tidal breaths are required to effectively inhale medication
from different types of spacer/ valved holding chamber devices, and to determine the
efficacy of a single maximal inhalation for drug delivery in young children.
⢠To investigate the relationship between factors that determine dose delivery of
inhaled asthma maintenance therapy and symptom control in preschool asthmatic children.
⢠To determine the influence of an incentive inhalation delivery device on drug
delivery and clinical outcome in preschool asthmatic children. Part One (Chapters Two and Three):
Background: The pMDI-spacer combination is currently the most commonly used method
of drug delivery to preschool asthmatics. A patientâs competence in using a pMDI-spacer
is an important part of drug delivery. Preschool children are instructed to breathe normally
(tidally) through spacer devices. There is little evidence on the number of breaths required
for optimal drug delivery. Whether the single maximal breath technique has a place in
spacer use in preschool children also remains unclear. Due to a lack of data, authors of
asthma guidelines have been unable to give evidence-based instruction on how a preschool
child should breathe through a spacer.
Aims: To determine the optimal method of breathing through a spacer for preschool
asthmatic children to ensure effective drug delivery.
Hypothesis: Based on technical data on in vitro spacer performance and knowledge of tidal
flow patterns in young children the hypothesis is that a limited number of breaths would be
sufficient for efficient drug inhalation via spacer in preschool children.
Methods: A method for reliably recording and simulating breathing of patients using
pMDI-spacer devices was designed, constructed and validated. Breathing flow patterns
were recorded in preschool children inhaling placebo from spacers. The breathing patterns
were reproduced by a breathing simulator which was connected to spacer devices.
Breathing patterns previously recorded using each specific type of spacer, were simulated
with the corresponding spacer type. To estimate delivery, the mass of salbutamol was
measured on a filter interposed between the spacer and the simulator. Four different spacer
devices, the Aerochamber Plus®, Funhaler®, Volumatic® and a modified 500ml plastic
soft drink bottle were tested with a salbutamol pMDI. The effect of different numbers of
tidal breaths and that of a single maximal breath on drug delivery were compared.
Results: Drug delivery via the Funhaler® mean (95CI) was 39% (34-43) and 38% (35-42)
of total dose recovered from filter, pMDI and spacer, for two and nine tidal breaths
respectively. Drug delivery via the Aerochamber Plus mean (95CI) was 40% (34-46) and
41% (36-47) for two and nine tidal breaths respectively. There was no significant difference in drug delivery after three tidal breaths mean (95CI) 40% (36-44%) and nine
tidal breaths nine tidal breaths; mean (95CI) 37% (33-41) for the Volumatic®. With the
(unvalved) modified soft drink bottle, there was no significant difference in drug delivery
between two, five or nine tidal breaths.
Inhalation volumes were almost double the expected tidal volumes. The inhalation volume
means (SD) of subjects using the Aerochamber Plus®, the Funhaler®, the Volumatic® and
the modified soft drink bottle were respectively 393ml (247), 432ml (225), 384ml (185),
445ml (167) during tidal breathing and 515ml (164), 550ml (239), 503ml (213), 448ml
(259) for the single maximal breath manoeuvre.
100% of seven year old children, 84% of six year olds, 76% of five year olds, 38% of four
year olds and 20% of three year olds could perform a single maximal breath manoeuvre.
Nine tidal breaths resulted in significantly greater drug delivery to filter than single
maximal inhalation for both the Funhaler® (p=0.04) and the Volumatic® (p=0.01). There
was no significant difference in drug delivery to filter between single maximal inhalation
and nine tidal breaths with both the Aerochamber Plus® and the modified soft drink bottle.
Conclusion: In preschool children, two tidal breaths were adequate for drug delivery
through small volume valved spacers and a 500ml modified soft drink bottle. For a large
volume spacer, three tidal breaths were adequate for drug delivery.
Part Two (Chapters Four and Five):
Background: Drug delivery by pMDI-spacer is determined by many different factors,
including spacer technique and adherence to prescribed medication. The effect of both
spacer technique and adherence on clinical outcome has been demonstrated in older
asthmatics. In this part of the thesis the influence of these factors on clinical outcome in
preschool asthmatics was firstly investigated. Thereafter, the additional influence of an
incentive spacer device on adherence, spacer technique and clinical outcome was also
assessed.
Aims:
⢠To investigate the effect of proficiency in spacer technique, as measured by
deposition of drug inhaled onto a filter, on clinical outcome in preschool asthmatic
children.
⢠To investigate the effect of adherence to prescribed inhaled asthma medication on
clinical outcome in preschool asthmatic children.
⢠To investigate the influence of the use of an incentive spacer device on inhaled drug
dose, adherence to prescribed treatment and clinical outcome in preschool asthmatic
children.
Hypothesis:
⢠Proficiency in spacer technique correlates positively with improved clinical
outcome.
⢠Good adherence to prescribed medication regimens correlates positively with
improved clinical outcome.
⢠Use of an incentive spacer device, the Funhaler® , improves both competency in
spacer technique and adherence to prescribed medication and thereby improves clinical
outcome in preschool children with asthma. Methods: A prospective randomised, controlled clinical trial was performed. Subjects
were two to six year old children who had doctor-diagnosed asthma and were on daily
maintenance therapy with inhaled corticosteroids. Maintenance therapy was delivered by
Funhaler® in the study group and Aerochamber Plus® in the control group. Subjects were
assessed for the following outcomes at three-monthly intervals for one year:
(1) Proficiency in spacer technique was measured at each study visit by measuring the
drug dose deposited on a filter interposed between the subject and the spacer.
(2) Adherence was monitored using an electronic monitoring device (Smartinhaler)
(3) Asthma symptoms were monitored using diary cards.
(4) Quality of life (QoL) was measured using the PedsQL questionnaires.
(5) Lung function was monitored using the forced oscillation technique.
The Funhaler group was then compared with the Aerochamber Plus group in terms of
determinants of drug delivery and markers of clinical outcome.
Results: One hundred and thirty two subjects were included in the study. One hundred and
eleven patients (84%) completed the study. By the six month follow-up, significantly more
subjects in the Funhaler group had dropped out of the study (p=0.04).
Throughout the clinical trial, there was large intra-subject variation in proficiency in spacer
technique, as measured by drug dose deposited on filter. Individual patient drug doses
recovered from the filters ranged from zero to 136μg (calculated as the mean of five 100μg
pMDI actuations). There was no significant correlation between proficiency in using the
delivery device and any measure of asthma control (p > 0.05). Correcting for age, gender,
and adherence to prescribed medication did not influence the results.
Inter subject variability in adherence to prescribed medication was extremely high
throughout the study. Adherence to prescribed medication ranged from 1% to 99%. There
was a significant correlation between adherence to prescribed medication and nights
without wheeze, throughout the study period (r = 0.01; p = 0.01). The correlation between
adherence to prescribed medication and nights without wheeze remained after correcting
for age, gender, proficiency in spacer technique, and the number of nights without wheeze
at the baseline visit (r = 0.01; p = <.01). There was also a significant correlation between
adherence to prescribed treatment and (daytime) days without wheeze (r = 0.01; p = 0.01).
The correlation ceased to be significant after correcting for age, gender, proficiency in spacer technique, and (daytime) days without wheeze at the time of the baseline visit.
There was a significant correlation between adherence to prescribed medication and
bronchodilator free days (r = 0.01; p = 0.02) throughout the study. After correcting for age,
gender, proficiency in spacer technique, and bronchodilator free days at baseline, the
correlation between adherence to prescribed medication and bronchodilator free days
remained significant (r = 0.01; p = 0.01). There was no significant correlation between
adherence and other markers of clinical outcome.
After correcting for age and gender, the Funhaler group demonstrated significantly higher
proficiency in spacer technique as determined by filter dose (p = 0.05). The improved
proficiency in spacer technique in the Funhaler group was limited to subjects who were
younger than 4 years of age at the baseline visit (p < 0.01).
There was no significant difference in adherence to prescribed medication between the
Funhaler group and the Aerochamber Plus group (p = 0.93). Correcting for age and gender
did not influence the results.
At the start of the clinical trial (baseline visit), the Funhaler group reported significantly
less days without wheeze (p = 0.03), and significantly less bronchodilator free days (p =
0.02) than the Aerochamber Plus group in the seven days before the baseline visit. The
Funhaler group also scored lower than the Aerochamber group in terms of QoL scores at
the time of randomisation (p = 0.05). Where needed, various measures were used to correct
for the significant differences at baseline, between the Funhaler group and the
Aerochamber Plus group. There was no significant difference between the Funhaler group
and the Aerochamber Plus group in terms any of clinical outcome measures used.
Correcting for age, gender did not influence the results.
Discussion: Use of the Funhaler® therefore appeared to specifically improve drug delivery
in those subjects who, with a conventional spacer, would have inhaled very low doses of
medication. The Funhaler® was therefore partially successful as an incentive device, as its
use positively influenced drug delivery in a specific sub-group of preschool children.
Proficiency in spacer technique did not translate to improved clinical outcomes. Various
reasons for the lack of association between proficiency in spacer technique and clinical outcome, including the inevitable inherent limitations in design in a clinical study, are
discussed.
Results suggest that adherence to prescribed medication regimens correlates positively with
improved clinical outcome in preschool children with asthma. Use of the Funhaler® did
not improve adherence to prescribed medication, or clinical outcome, in preschool children
with asthma. Funhaler® therefore failed as an incentive device to improve long term
adherence, and clinical outcome, in preschool asthmatic children. Future design for an
incentive device will need to consider providing feedback that is of more ongoing interest
to the child.
As the large variation, as observed in this study, in proficiency in spacer technique, and
adherence to prescribed medication, is likely to influence results of clinical trials, an
awareness of the variation in spacer technique and drug delivery may contribute towards
the accurate interpretation of results in future studies.
Finally, the wide variation in both proficiency in spacer technique, and adherence to
prescribed medication, both factors that determine drug delivery to patients, highlight the
importance of pursuing ways to improve inhalation drug delivery to preschool children in
order to eliminate the variability in prescribed medication that eventually reaches patients.
The delivery to the lungs of a constant, reliably repeatable inhaled drug dose should be a
continuing aim for aerosol scientists and physicians.
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THE DYNAMICS OF BUSH THICKENING BY ACACIA MELLIFERA IN THE HIGHLAND SAVANNA OF NAMIBIAJoubert, David Francois 19 August 2014 (has links)
The dynamics of bush thickening by Acacia mellifera in the arid Namibian Highland Savanna was investigated. First, a conceptual state-and-transition model was developed, based on preliminary findings, personal observations and resultant insights. In this model it was proposed that two main states exist, an open, grassy state and a bush-thickened state. Each of these is subdivided into other states. An unstable transitional state with A. mellifera seedlings within the grass sward is a crucial juncture between the grassy and bush thickened state. In the model, the transition to this unstable state occurs after at least two, but more likely three, consecutive years of well above-average annual rainfall through seed production followed by germination and establishment. Only an interruption by fire, which has a high probability of coinciding with this establishment if the grass sward is lightly utilised, prevents a further transition to a bush thickened state. Fire returns the vegetation to a grassy state by causing an almost 100 % mortality of seedlings. If fire is absent through a lack of fuel (overgrazing) or fire is deliberately excluded, the transition to a bush-thickened state is a fait accompli, but may take decades to reach. Transitions from the bush-thickened state to a grassy state require drought and the associated fungal dieback, which accelerates the senescence of mature shrubs. The model proposes that a transition towards the unstable transitional state occurs rarely, due to the rarity of suitable climatic conditions (protracted period of consecutive years of above-average annual rainfall). The mechanisms of two key transitions were tested. Firstly, the transition to an unstable state through the en masse production of seeds followed by the successful establishment of seedlings after a protracted period of well above average rainfall was tested during a nine-year period (late 1998 to early 2007). Secondly, the transition back to an open grassy state during a potential establishment event, through the mortality of seedlings after a fire, was tested experimentally (2008 and 2009). Both of these studies confirmed the predictions of the model and the mechanisms proposed for these transitions. Preliminary evidence suggests that browsing by small herbivores, in particular lagomorphs, thins resultant thickets out through herbivory. Preliminary evidence also suggests that competition between grasses and seedlings does not directly stop the transition to a bush thickened state but may prolong the window of opportunity for a fire to be effective, through reducing the growth rate of seedlings and saplings. The findings are of relevance to management, and thus an expert system for rangeland management, with emphasis on bush thickening, was developed, based largely on the findings of this research.
Preliminary historical evidence casts doubt upon the prevailing perception that bush thickening is mostly a phenomenon of the last half century, and, consequently, that bush thickening is the primary cause of the loss of rangeland productivity in the arid rangelands of Namibia during this period. The study suggests that fire in arid savannas is as important as it is in mesic savannas. A general principle could be stated as follows: The importance of the timing of fire in savannas increases with increasing aridity, whilst the importance of the frequency of fire in savannas decreases with increasing aridity.
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EVALUATION OF LIGAND MODIFIED PALLADIUM CATALYSTS IN THE WACKER OXIDATION OF ALKENESSaku, Duduetsang 19 August 2014 (has links)
The industrial application of Wacker oxidation of terminal olefins in aqueous aerobic mixtures with PdCl2 and CuCl/CuCl2 has largely been limited to shorter chain alkenes, that is, ethylene. As the alkene chain length increases, so do the challenges that render the reaction inapplicable for large scale production. Longer chain alkenes tend to isomerize due to the limited solubility in organic-aqueous mixtures. More so, the use of co-oxidants such as CuCl or CuCl2 in stoichiometric amounts results in the formation of toxic chlorinated by-products which make the system corrosive. Pd0 aggregation from the PdII active state, is also pertinent in these reactions hence the use of large amounts of a co-oxidant. Small TONs and TOFs have subsequently been reported. As one of the approaches to curb these challenges, ligand support and modification has recently been viewed with interest because it promises efficient stabilization of Pd0, wherein the efficiency of O2 to re-oxidize the Pd0 species is relied upon thereby avoiding Pd0 aggregation. Ligand support can also be used to alter the electronic environment of the PdII centre thereby affecting its activity and selectivity.
The application of phosphorus-palladium complexes in this study is not only a new approach in Wacker oxidation but the utilization of the Ï-accepting and or Ï-donating abilities of phosphorus compounds was also advantageous in altering the PdII electronic environment. No co-oxidants were used in this study w.r.t. the oxidation of 1-octene and the complexes evaluated were comparable to those reported in literature with PdCl2/DMA systems under similar conditions. Since oxygen is the preferred oxidant in all oxidation reactions because of its natural abundance, its reported enhanced selectivity and ease of separation from products, it was decided to evaluate the utilization of this reagent as first choice in the current investigation of ligand supported palladium catalysts in the Wacker oxidation.
Due to the fact that the phosphite based palladium catalyst, PdCl2[P(OPh)3]2, is readily soluble in DMA, it was determined that no pre-stirring as for PdCl2 was required for this catalyst. In order to obtain the optimum reaction conditions for oxygen as oxidant with this catalyst, conditions like solvent, reaction temperature, O2 pressure and water, catalyst, and substrate concentration were varied. The optimized conditions were determined to be 0.5 mol% of catalyst in DMA:H2O (6:1) under 9 atm of O2 at 80°C, while the optimum substrate concentration was found to be 0.2M. PdCl2[P(OPh)3]2 showed the highest activity of the catalysts evaluated and gave a TOF of >1370 (mol/mol/hr), which compared favourably with other known catalysts like PdCl2, PdCl2(CH3CN)2 Pd(OAc)2, and Pd(CF3SO3)2 where TOFâs of 1429, 1420, 817 and 524 respectively, were obtained under the conditions optimized for PdCl2[P(OPh)3]2. While the palladium metallocycle [Pd(u-Cl)(C6H4O)(OC6H6)2]2 gave TOFâs (1380 mol/mol/hr) virtually the same as PdCl2[P(OPh)3]2, total conversion for the latter catalyst was only 93%, so it can be regarded as the second best of all the catalysts evaluated. The monomers thereof, PdCl[(C6H4O)(C6H6O)2P(OPh3)] and PdCl[(C6H4O)(C6H6O)2(PPh3)], revealed the least basic P(OPh3) to be more reactive (TOF >900 mol/mol/hr) than the TPP containing analogue, where the latter showed no activity within the first hour of reaction. While all the active catalysts showed good selectivities of >80%, the metallocycle [Pd(u-Cl)(C6H4O)(OC6H6)2]2 proved to be the best with a selectivity of 89%. Catalyst recyclability was also observed to at least 3 cycles, with selectivities maintained above 80%. No Pd0 âfall-outâ or aggregation was observed with any of the catalysts evaluated.
For the palladium phosphinite catalysts 1,2-Ph(OPPh2)2PdCl2 and 1,3-Ph(OPPh2)2PdCl it was found that both were active in the Wacker oxidation of 1-octene albeit with very low rates for the latter complex (1,3-Ph(OPPh2)2PdCl). The low reactivity of 1,3-Ph(OPPh2)2PdCl was similar to that of the phosphines (PPh3)2PdCl2 and (3,5-CF3-PPh2Cl)2PdCl2 where (PPh3)2PdCl2 showed some conversion only after 3 hours and (3,5-CF3-PPh2Cl)2PdCl2 gave only 53% conversion after an hour. Through a comparison of the reactivity of 1,2-Ph(OPPh2)2PdCl2 with that of the hydrolyzed equivalent [μ-ClPd(PPh2OH)(PPh2O)]2, it seemed as if the phosphinite catalysts are prone to hydrolysis under the prevailing conditions as the final conversion of both these catalysts were almost the same (85 and 79% respectively).
Hydrogen peroxide and tert-butylhydroperoxide (TBHP) were also evaluated as alternative oxidants with PdCl2[P(OPh)3]2 as catalyst and H2O2 was found to be the better of the two oxidants with conversion (99%), selectivity (86%), and TOF (1220) almost as good as those found for oxygen (100, 82% and 1370 respectively). In addition, the catalyst could also be recycled three times although degradation of the H2O2 was observed and additional peroxide (12 eq.) had to be added with each cycle of substrate. TBHP, however, suffered from moderate selectivities of only 60-65%, while the catalysts was deactivated during the first oxidation cycle and could therefore not be recycled at all.
Although all phosphite catalysts promoted isomerization to internal 1-octene isomers to some extent, the cyclopalladated [Pd(u-Cl)(C6H4O)(OC6H6)2]2 catalysts proved to be the best in this aspect of the reaction w.r.t. oxygen as oxidant and led to very low quantities of isomerised products being observed (3 - 4%). It was also evident that the type and amount (for H2O2 and TBHP) of oxidant played a crucial role in enhancing or suppressing isomerization and hydrogen peroxide (at only 2% isomerization) was found to be the best oxidant in this regard followed by oxygen (13%).
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A national profile of athletic academic advising in NCAA division institutions /Brubaker, Dale M. January 1991 (has links)
Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1991. / Vita. Abstract. Includes bibliographical references (leaves 55-56). Also available via the Internet.
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Qualities of faculty members who are successful teachers and advisors of international students /Jones, Ralph. January 1988 (has links)
Thesis (Ed.D.)--Teachers College, Columbia University. / Typescript; issued also on microfilm. Sponsor: Thomas A. Leemon. Dissertation Committee: Samuel D. Johnson. Bibliography: leaves 138-147.
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A helping hand : a mentoring program between staff and students /Norcia, Beth Frances. January 1900 (has links)
Thesis (M.A.)--Rowan University, 2005. / Typescript. Includes bibliographical references.
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