The effect of hetero-atoms on spin exchange coupling pathways (ECPs): a computational investigation.

The effect of heteroatoms on exchange coupling pathways and the presence of more than one coupling paths are investigated. The lone pairs of sp2-hybridized heteroatoms contribute to aromaticity but do not play any pivotal role in the spin coupling between two spin centers. A conceptual model to describe this behavior of heteroatoms has been introduced, and we name it as the hetero-atom blocking effect. With the occurrence of two π-orbital exchange coupling pathways (ECPs) via bridgehead heteroatoms (B-, N-, O-, or S-), the magnetic exchange coupling constants (J) can be viewed as a signed sum of different individual pathways. The effect of σ-electron coupling is also investigated in this work.

Diborane Concatenation Leads to New Planar Boron Chemistry.

Diborane has long been realized to be analogous to ethylene in terms of its bonding MOs, both as to symmetries and splitting patterns. This naturally suggests an investigation to see whether other similar conjugated hydrocarbons manifest a similar boron-substituted and H2 supplemented borane. That is, for a conjugated hydrocarbon structure with a neighbor-paired resonance pattern, we propose to look at boranes where each carbon atom is replaced by a boron atom, and an H-atom pair is added to each double bond of the resonance structure, with one H above the molecular plane and one below. This construction of concatenated diboranes is uniformly different than that for the previously known stable boranes of 4 or more B atoms. We find from quantum-chemical computations that our so constructed polyboranes are stable. All this suggests a possible novel new chapter in borane chemistry - a chapter with some promise of understandings related to that for (alternant) conjugated hydrocarbons.

Collaborative team-based health promotion in a primary care setting: The MOVE program.

OBJECTIVE: To assess a primary care-based, physician-led physical activity program for primary care patients. DESIGN: Initial assessment of a physical activity program for feasibility, patient satisfaction, and effectiveness. SETTING: A primary care network in Edmonton, Alta. PARTICIPANTS: Patients from the primary care network. INTERVENTION: The MOVE program is a primary care-based, physician-led physical activity program for primary care patients, collaboratively offered by an FP and a kinesiologist. MAIN OUTCOME MEASURES: Six-minute walk test and patient survey results. RESULTS: Patients reported considerable benefits to participating in the MOVE program. Improvements in 6-minute walk test results were observed over 2 months (587 vs 653 m, P < .001). CONCLUSION: Being involved in innovative primary care-based health promotion activities is a way for FPs to achieve success in changing patients' behaviour.

Toward Molecular Magnets of Organic Origin via Anion-π Interaction Involving m-Aminyl Diradical: A Theoretical Study.

Here we study a set of novel magnetic organic molecular species with different halide ions (fluoride, chloride, bromide) absorbed ∼2 Å above or below the center of an aromatic π-ring in an m-aminyl diradical. Focus is on the nature of anion-π interaction and its impact on magnetic properties, specifically on magnetic anisotropy and on intramolecular magnetic exchange coupling. In the development of single molecule magnets, magnetic anisotropy is considered to be the most influential factor. A new insight regarding the magnetic anisotropy that determines the barrier height for relaxation of magnetization of m-aminyl diradical-derived anionic complexes is obtained from calculations of the axial zero-field-splitting (ZFS) parameter D. The noncovalent anion-π interaction strongly influences magnetic anisotropy in m-aminyl-halide diradical complexes. In particular, the change of D values from positive (for the m-aminyl diradical, m-aminyl diradical/fluoride, and m-aminyl diradical/chloride complexes) to negative D-values in m-aminyl diradical complexes containing bromide signals a change from oblate to prolate type of spin-density distribution. Furthermore, the noncovalent halide-π interactions lead to large values of intramolecular magnetic exchange coupling coefficients J exhibiting a ferromagnetic sign. The magnitude of J steadily increases going from anionic complexes containing fluoride to chloride and then to bromide. Relations are sought between the magnetic exchange coupling coefficients J and aromaticity, namely structural HOMA (harmonic oscillator model of aromaticity) and magnetic NICS (nucleus independent chemical shift) aromaticity indices, in particular, the NICSzz(+1) component. Finally, possible numerical checks on the conditions relating to validity of the well-known Yamaguchi's formula for calculating the exchange coupling coefficient J in diradical systems are discussed.

A high-spin organic diradical as a spin filter.

Here, in this work we have designed a molecular bridge structure which can be used as a spin filter where the prototypical highly ferromagnetic m-phenylene connected bis(aminoxyl) diradical is used as a bridging fragment between two semi-infinitely widened gold (Au) electrodes along the [100] direction. A state-of-the-art non-equilibrium Green function's (NEGF) method coupled with the density functional theory (DFT) was carried out on this two-probe molecular bridge system to understand its electrical spin transport characteristics. The spin current at various bias voltages from 0.00 V to 4.00 V at intervals of 0.20 V for this Au-diradical-Au molecular junction is evaluated. We also quantify the bias-dependent spin injection coefficients (BDSIC) at different bias voltages and also the spin-filter efficiency at equilibrium, i.e., at zero bias voltage. Also plots of BDSIC vs. voltage, the up- and down-spin current vs. voltage (I-V) curves, and density of states (DOS) at zero bias voltage are evaluated.

Borazine: spin blocker or not?

The spin blocker capacity of borazine is investigated. Specifically, meta-B-B, meta-N-N and para-B-N connected borazines are used as spin-blocker couplers comprised of a pair of radicals: two iminonitroxides (IN); IN and tetrathiafulvalene radical cations (TTF); or two TTFs. Density functional theory (DFT) is used to elucidate the spin blocker capacity of the linkage-specific (meta or para) borazine-coupler and elaborate the role of the lowest unoccupied molecular orbital (LUMO) in magnetic-exchange. Furthermore, a qualitative relation between different magnetic aromaticity indices is made using both nuclear-independent chemical shift (NICS) and the harmonic oscillator model of aromaticity (HOMA). The NICS values are calculated at the centre of the borazine spacer fragment of these diradical species and then also at 0.5 Å increments of the virtual probe from this centre position up to an orthogonal distance of 2.0 Å from the centre. The HOMA values are calculated for the borazine ring fragment in these diradicals. Based on the HOMA and NICS values, it is evident that the borazine exhibits less aromatic character than benzene itself - due to the polar nature of B-N π-bonding. The LUMO mediated spin-exchange between the two consecutive singly occupied molecular orbitals (SOMOs) is explicitly discussed and confirmed to play a pivotal role. The parity of the coupler pathways, i.e. even or odd number of bonds along a selected pathway, between radical moieties is an important factor in predicting the nature and extent of magnetic exchange for these diradicals. Surprisingly, borazine does not always act as a spin-coupling blocker - rather in some cases the coupling is enhanced as compared to a homoatomic (carbon-based) benzene coupler.

Clar theory extended for polyacenes and beyond.

An extension of Clar's classical sextet ideas is presented to allow resonance-based weak-pairing long bonds. As the prototypic illustration, the theory is developed in the context of polyacenes, where this extension is needed to properly understand what goes on in this sort of polymer, whose radicality increases with chain length. A quantification of these novel Clar-sextic ideas is made, and detailed computational results are reported for the polyacenes even to the limit of arbitrary long chains. Resonance energies, bond lengths, and local (ring) aromaticity indices are addressed. It is emphasized that weak pairing is not at all unique to the polyacenes, but also applies whenever there are suitable boundaries (say of the "zig-zag" type) on general grapheneic structures--thereby readily explaining novel features of different boundaries.

Flow network QSAR for the prediction of physicochemical properties by mapping an electrical resistance network onto a chemical reaction poset.

Usual quantitative structure-activity relationship (QSAR) models are computed from unstructured input data, by using a vector of molecular descriptors for each chemical in the dataset. Another alternative is to consider the structural relationships between the chemical structures, such as molecular similarity, presence of certain substructures, or chemical transformations between compounds. We defined a class of network-QSAR models based on molecular networks induced by a sequence of substitution reactions on a chemical structure that generates a partially ordered set (or poset) oriented graph that may be used to predict various molecular properties with quantitative superstructure-activity relationships (QSSAR). The network-QSAR interpolation models defined on poset graphs, namely average poset, cluster expansion, and spline poset, were tested with success for the prediction of several physicochemical properties for diverse chemicals. We introduce the flow network QSAR, a new poset regression model in which the dataset of chemicals, represented as a reaction poset, is transformed into an oriented network of electrical resistances in which the current flow results in a potential at each node. The molecular property considered in the QSSAR model is represented as the electrical potential, and the value of this potential at a particular node is determined by the electrical resistances assigned to each edge and by a system of batteries. Each node with a known value for the molecular property is attached to a battery that sets the potential on that node to the value of the respective molecular property, and no external battery is attached to nodes from the prediction set, representing chemicals for which the values of the molecular property are not known or are intended to be predicted. The flow network QSAR algorithm determines the values of the molecular property for the prediction set of molecules by applying Ohm's law and Kirchhoff's current law to the poset network of electrical resistances. Several applications of the flow network QSAR are demonstrated.

Monitoring of international normalized ratios: comparison of community nurses with family physicians.

OBJECTIVE: To determine whether community-based, nurse-led monitoring of the international normalized ratio (INR) in patients requiring long-term warfarin therapy was comparable to traditional physician monitoring. DESIGN: A retrospective cohort analysis of patients taking long-term warfarin therapy. SETTING: The study used data gathered from 3 family medicine clinics in a primary care network in Edmonton, Alta. PARTICIPANTS: Medical records of patients currently taking warfarin were examined. INTERVENTION: Implementation of nurse-led monitoring in a primary care network in place of standard family physician INR monitoring. MAIN OUTCOME MEASURES: The degree of INR control before and after the implementation of nurse-run INR monitoring was assessed. The average proportion of time spent outside of therapeutic INR ranges, as well as the average number of days between successive INR readings, was calculated and compared. The degree of control placed patients into either a good-control group (out of range ≤ 25% of the time) or a moderate-control group (out of range > 25% of the time) and these groups were compared. RESULTS: Before nurse monitoring, INR values were out of range 20.4% of the time; after nurse monitoring they were out of range 19.2% of the time (P = .115); the time between sequential INR readings also did not differ before and after implementation of nurse monitoring (23.9 vs 21.6 days, P = .789). CONCLUSION: Nurse-led monitoring of INR is as effective as traditional physician monitoring. Advantages of nurse-led monitoring might include freeing family physicians to see more patients or to spend less time at work. It might also represent potential cost savings.

Are family physicians using the CHADS2score? Is it useful for assessing risk of stroke in patients with atrial fibrillation?

OBJECTIVE: To assess whether family physicians are using the CHADS(2) (congestive heart failure, hypertension, age ≥ 75, diabetes mellitus, and stroke or transient ischemic attack) score in the decision to initiate warfarin therapy to prevent stroke in patients with atrial fibrillation. DESIGN: Retrospective analysis of the medical records of patients with atrial fibrillation. SETTING: Data were gathered from records at 3 clinics in a primary care network in Edmonton, Alta. PARTICIPANTS: The medical records of patients with atrial fibrillation who were currently taking warfarin therapy. MAIN OUTCOME MEASURES: Percentage of patients whose CHADS(2) scores indicated warfarin therapy for stroke prophylaxis compared with the actual percentage of patients taking warfarin therapy. Data on patients' age, number of medications, and number of comorbid conditions were also recorded. RESULTS: Among these patients, 7% had a CHADS(2) score of 0, for which no warfarin therapy was indicated; 21% had a score of 1, for which either acetylsalicylic acid or warfarin was indicated; and 72% had a score of 2 or greater, for which warfarin therapy was indicated. About 80% of patients were taking medication to control their heart rate. CONCLUSION: The CHADS(2) score is not being used in all cases to assess the need for warfarin therapy for preventing stroke in patients with atrial fibrillation. The CHADS(2) score might be of limited use because it is not sensitive enough to stratify patients clearly into high-, intermediate-, and low-risk groups. Although guidelines for stroke prevention should be followed, the CHADS(2) portion of the guidelines might not be the most effective way to assess patients' risk of stroke.

Partially ordered sets: ranking and prediction of substances' properties.

There are at least two significant applications of partial order theory in chemistry: Ranking methods and substances' properties prediction. In both cases, a set of objects is endowed with a partial order relation e.g. "more polluting than", "can be obtained from", "more reactive than" etc. The couple of set and partial order relation is known in mathematics as a partially ordered set (poset). Ranking methods, such as the Hasse diagram technique, lead to a partial order where several incomparabilities (lack of order) appear between pairs of objects. This phenomenon is quite common in ranking studies, and it often is circumvented by a combination of object features leading to a total order. However, such a combination introduces subjectivities and bias in the ranking process. Here a step-by-step procedure is shown to turn incomparabilities into comparabilities taking into account all the possible bias by a linear combination of features. In such a manner, it is possible to predict how probable it is to obtain a particular total order from a given poset. Similarly, it is possible to calculate the needed bias over certain attributes to obtain a particular total order. An example application is shown where substances are ranked according to their bioconcentration factor and biodegradation potential. Another application of partial order theory to chemistry has to do with the prediction of properties for a set of substances related in a (preferably systematic) chemical fashion. A customary relation is "can be obtained from"; if such a relation is set up for a given molecular structure e.g. benzene, and all its substituted derivatives (say chlorinated ones) are considered, then the set of benzene and its chlorinated derivatives are partially ordered. Taking advantage of the poset generated, different methods can be applied to predict properties of the substances considered in the poset. Such methods include the poset-average, cluster expansion, and splinoid methods. In this paper we discuss each one of these methods, its advantages and disadvantages and we outline its applicability to estimate cooperative free energies of hemoglobins with different degree of oxygenation.

Do randomized controlled trials discuss healthcare costs?

BACKGROUND: Healthcare costs, particularly pharmaceutical costs, are a dominant issue for most healthcare organizations, but it is unclear if randomized controlled trials (RCTs) routinely discuss costs. Our objective was to assess the frequency and factors associated with the inclusion of costs in RCTs. METHODS AND FINDINGS: We randomly sampled 188 RCTs spanning three years (2003-2005) from six high impact journals. The sample size for RCTs was based on a calculation to estimate the inclusion of actual drug costs with a precision of +/-3%. Two reviewers independently extracted cost data and study characteristics. Frequencies were calculated and potential characteristics associated with the inclusion of costs were explored. Actual drug costs were included in 4.7% (9/188) of RCTs; any actual costs were included in 7.4% (14/188) of RCTs; and any mention of costs was included in 27.7% (52/188) of RCTs. As the amount of industry funding increased across RCTs, from non-profit to mixed to fully industry funded RCTs, there was a statistically significant reduction in the number of RCTs with any actual costs (Cochran-Armitage test, p = 0.005) and any mention of costs (Cochran-Armitage test, p = 0.02). Logistic regression analysis also indicated funding was associated with the inclusion of any actual cost (OR = 0.34, p = 0.009) or any mention of costs (OR = 0.63, p = 0.02). Journal, study conclusions, study location, primary author's country and product age were not associated with inclusion of cost information. CONCLUSION: While physicians are encouraged to consider costs when prescribing drugs for their patients, actual drug costs were provided in only 5% of RCTs and were not mentioned at all in 72% of RCTs. Industry funded trials were less likely to include cost information. No other factors were associated with the inclusion of cost information.

Push, pull, and plant: the personal side of physician immigration to alberta, Canada.

BACKGROUND AND OBJECTIVES: The global migration of physicians has led many international physicians to enter practice in Alberta, Canada. The study was designed to explore the personal side of migration and transition experiences of these international medical graduates (IMGs). METHODS: A qualitative study using telephone interviews and a semi-structured interview guide was used to interview 19 IMGs who are currently practicing and have held Part V, restricted or temporary practice licenses for less than 7 years. RESULTS: Three major themes were identified. The first was the "push" from their own country of origin and their perception that moving to Alberta would be better for them. Professional opportunities in their home country had been affected by changing policies, lack of infrastructure, and personal/family safety issues culminating in highly stressful work environments. The second was "pull." An improvement in the quality of personal life was associated with geographical, educational, recreational, and spiritual aspects of daily living for participants and their families in their new environment. The third theme was "plant"ie, factors that encouraged them to stay in Alberta. CONCLUSIONS: This study demonstrates the continued relevance of push and pull theory in understanding IMG physician migration. Our findings in this study indicate that remaining in place, or "being planted" is conditional on political, social, and economic aspects.

Who is driving continuing medical education for family medicine?

INTRODUCTION: Considerable time and money are invested in continuing medical education (CME) for family physicians (FPs) but the effectiveness is uncertain. The participation of FPs as coordinators and teachers is not well known. The goal of this project was to describe the role of FPs in organizing and teaching CME events that are accredited for FPs. METHODS: Information about accredited CME events occurring in Alberta and Nova Scotia was requested from universities, provincial chapters of the College of Family Physicians of Canada, and pharmaceutical companies. Location, coordinating site, organizing committee members, teaching faculty, and format were recorded from each event. The number and proportion of FPs involved in both organizing and teaching CME events accredited for FPs were calculated and compared. RESULTS: A total of 314 CME events were collected, comprising a total of 1,472 hours of CME. From the CME events collected, there were 1,730 organizing committee members and 1,647 teachers. FPs constitute 59% of the organizing committees and 17% of the teachers. Significant differences in the numbers of FP planners and teachers were related to organizing group, format, location, and expected audience composition. DISCUSSION: The accreditation requirement for FPs on organizing committees likely helps preserve a reasonable proportion of FP organizers but not teachers in FP CME. The proportions of true FP planners and teachers may actually be lower than planning documents indicate. Low level of family physician teachers in CME may be due to FPs' not selecting FP teachers, the FP teaching pool's being inadequate, or the organizing committee's being unaware of FPs who are knowledgeable in particular areas.

Combinatorics of reaction-network posets.

Reaction networks are viewed as derived from ordinary molecular structures related in reactant-product pairs so as to manifest a chemical super-structure. Such super-structures then are candidates for applications in a general combinatoric chemistry. Notable additional characterization of a reaction super-structure occurs when such reaction graphs are directed, as for example when there is progressive substitution (or addition) on a fixed molecular skeleton. Such a set of partially ordered entities is in mathematics termed a poset, which further manifests a number of special properties, as then might be utilized in different applications. Focus on the overall "super-structural" poset goes beyond ordinary molecular structure in attending to how a structure fits into a (reaction) network, and thereby brings an extra "dimension" to conventional stereochemical theory. The possibility that different molecular properties vary smoothly along chains of interconnections in such a super-structure is a natural assumption for a novel approach to molecular property and bioactivity correlations. Different manners to interpolate/extrapolate on a poset network yield quantitative super-structure/activity relationships (QSSARs), with some numerical fits, e.g., for properties of polychlorinated biphenyls (PCBs) seemingly being quite reasonable. There seems to be promise for combinatoric posetic ideas.

Family medicine curriculum: improving the quality of academic sessions.

UNLABELLED: PROBLEM ADDRESSED The Family Medicine Residency Program at the University of Alberta has used academic sessions and clinical-based teaching to prepare residents for private practice. Before the new curriculum, academic sessions were large group lectures given by specialists. These sessions lacked consistent quality, structured topics, and organization. OBJECTIVE OF PROGRAM: The program was designed to improve the quality and consistency of academic sessions by creating a new curriculum. The goals for the new curriculum included improved organizational structure, improved satisfaction from the participants, improved resident knowledge and confidence in key areas of family medicine, and improved performance on licensing examinations. PROGRAM DESCRIPTION: The new curriculum is faculty guided but resident organized. Twenty-three core topics in family medicine are covered during a 2-year rotating curriculum. Several small group activities, including problem-based learning modules, journal club, and examination preparation sessions, complement larger didactic sessions. A multiple-source evaluation process is an essential component of this new program. CONCLUSION: The new academic curriculum for family medicine residents is based on a variety of learning styles and is consistent with the principles of adult learning theory. This structured curriculum provides a good basis for further development. Other programs across the country might want to incorporate these ideas into their current programming.