Impact of severity and type of depression on quality of life in cases identified in the community

BACKGROUND

The impact of different levels of depression severity on quality of life (QoL) is not well studied, particularly regarding ICD-10 criteria. The ICD classification of depressive episodes in three levels of severity is also controversial and the less severe category, mild, has been considered as unnecessary and not clearly distinguishable from non-clinical states. The present work aimed to test the relationship between depression severity according to ICD-10 criteria and several dimensions of functioning as assessed by Medical Outcome Study (MOS) 36-item Short Form general health survey (SF-36) at the population level.

METHOD

A sample of 551 participants from the second phase of the Outcome of Depression International Network (ODIN) study (228 controls without depression and 313 persons fulfilling ICD criteria for depressive episode) was selected for a further assessment of several variables, including QoL related to physical and mental health as measured with the SF-36.

RESULTS

Statistically significant differences between controls and the depression group were found in both physical and mental markers of health, regardless of the level of depression severity; however, there were very few differences in QoL between levels of depression as defined by ICD-10. Regardless of the presence of depression, disability, widowed status, being a woman and older age were associated with worse QoL in a structural equation analysis with covariates. Likewise, there were no differences according to the type of depression (single-episode versus recurrent).

CONCLUSIONS

These results cast doubt on the adequacy of the current ICD classification of depression in three levels of severity.

Polylactide-poly(dimethylsiloxane)-polylactide triblock copolymers as multifunctional materials for nanolithographic applications

Highly immiscible block copolymers are attractive materials for applications in nanolithography due to their ability to self-assemble on length scales that are difficult to access by conventional lithography. The incorporation of inorganic domains into such block copolymers provides etch contrast that can potentially reduce processing times and costs in nanolithographic applications. We explored thin films of polylactide-poly(dimethylsiloxane)-polylactide (PLA-PDMS-PLA) triblock copolymers as multifunctional nanolithographic templates. We demonstrate the formation of well-ordered arrays of hexagonally packed PDMS cylinders oriented normal to the substrate, the orthogonal etchability of these cylinders and the PLA matrix, and the formation of etch-resistant domains that can be used as pattern transfer masks.

Bulk spin polarization of Co(1-x)Fe(x)S2

We report on a new method to determine the degree of bulk spin polarization in single crystal Co(1-x)Fe(x)S2 by modeling magnetic Compton scattering with ab initio calculations. Spin-dependent Compton profiles were measured for CoS2 and Co0.9Fe0.1S2. The ab initio calculations were then refined by rigidly shifting the bands to provide the best fit between the calculated and experimental directional profiles for each sample. The bulk spin polarizations, P, corresponding to the spin-polarized density of states at the Fermi level, were then extracted from the refined calculations. The values were found to be P=-72+/-6% and P=18+/-7% for CoS2 and Co0.9Fe0.1S2, respectively. Furthermore, determinations of P weighted by the Fermi velocity (v(F) or v(F)2) were obtained, permitting a rigorous comparison with other experimental data and highlighting the experimental dependence of P on v(F).

The minority spin surface bands of CoS(2)(001)

Angle-resolved photoemission was used to study the surface electronic band structure of high quality single crystals of ferromagnetic CoS(2) (below 120 K). Strongly dispersing Co t(2g) bands are identified along the ⟨100⟩ [Formula: see text] direction, the [Formula: see text]-[Formula: see text] line of the surface Brillouin zone, in agreement with model calculations. The calculated surface band structure includes corrections for the previously determined surface structure of CoS(2)(001) and is in general agreement with the experimental photoemission spectra in the region of the Fermi level. There is evidence of the existence of several minority spin surface states, falling into a gap of the projected minority spin bulk CoS(2)(001) band structure.

Composite block polymer-microfabricated silicon nanoporous membrane

Block polymers offer an attractive route to densely packed, monodisperse nanoscale pores. However, their fragility as thin films complicates their use as membranes. By integrating a block polymer film with a thin (100 microm) silicon substrate, we have developed a composite membrane providing both nanoscale size exclusion and fast transport of small molecules. Here we describe the fabrication of this membrane, evaluate its mechanical integrity, and demonstrate its transport properties for model solutes of large and small molecular weight. The ability to block large molecules without hindering smaller ones, coupled with the potential for surface modification of the polymer and the microelectromechanical system style of support, makes this composite membrane an attractive candidate for interfacing implantable sensing and drug-delivery devices with biological hosts.

Composition controlled spin polarization in Co(1-x)Fe(x)S(2) alloys

The transition metal (TM) chalcogenides of the form TMX(2) (X = S or Se) have been studied for decades due to their interesting electronic and magnetic properties such as metamagnetism and metal-insulator transitions. In particular, the Co(1-x)Fe(x)S(2) alloys were the subject of investigation in the 1970s due to general interest in itinerant ferromagnetism. In recent years (2000-present) it has been shown, both by electronic structure calculations and detailed experimental investigations, that Co(1-x)Fe(x)S(2) is a model system for the investigation of highly spin polarized ferromagnetism. The radically different electronic properties of the two endpoint compounds (CoS(2) is a narrow bandwidth ferromagnetic metal, while FeS(2) is a diamagnetic semiconductor), in a system forming a substitutional solid solution allows for composition control of the Fermi level relative to the spin split bands, and therefore composition-controlled conduction electron spin polarization. In essence, the recent work has shown that the concept of 'band engineering' can be applied to half-metallic ferromagnets and that high spin polarization can be deliberately engineered. Experiments reveal tunability in both sign and magnitude of the spin polarization at the Fermi level, with maximum values obtained to date of 85% at low temperatures. In this paper we review the properties of Co(1-x)Fe(x)S(2) alloys, with an emphasis on properties of relevance to half-metallicity. Crystal structure, electronic structure, synthesis, magnetic properties, transport properties, direct probes of the spin polarization, and measurements of the total density of states at the Fermi level are all discussed. We conclude with a discussion of the factors that influence, or even limit, the spin polarization, along with a discussion of opportunities and problems for future investigation, particularly with regard to fundamental studies of spintronic devices.

Direct measurement of the low-temperature spin-state transition in LaCoO3

LaCoO3 exhibits an anomaly in its magnetic susceptibility around 80 K associated with a thermally excited transition of the Co3+-ion spin. We show that electron energy-loss spectroscopy is sensitive to this Co3+-ion spin-state transition, and that the O K edge prepeak provides a direct measure of the Co3+ spin state in LaCoO3 as a function of temperature. Our experimental results are confirmed by first-principles calculations, and we conclude that the thermally excited spin-state transition occurs from a low to an intermediate spin state, which can be distinguished from the high-spin state.

The dose–volume interaction in adult supratentorial low-grade glioma: higher radiation dose is beneficial among patients with partial resection

PURPOSE

To evaluate the hypothesis that adults with partially resected (PR<50% resection) supratentorial low-grade glioma (LGG) benefit from higher doses of radiation.

METHODS

Patients receiving post-operative radiation for WHO grade I-II LGG at the University of Western Ontario between 1979 and 2001 were studied. Patient characteristics evaluated included: age, gender, symptom duration>30 days, seizures at presentation, Karnofsky performance status (KPS)<70, astrocytoma pathology (AS), and radiation dose. A Cox proportional hazard regression model was constructed to test the influence of radiation dose.

RESULTS

One hundred and seven patients were analyzed. Patients who had PR were not significantly different from those with STR (subtotal/total resection) in terms of patient characteristics. Median survival (MST) of PR patients who received<or=50 Gy was 16.5 months while those who received>50 Gy had a MST of 109.2 months. The interaction of radiation dose and extent of resection was tested after controlling for other patient factors by Cox regression model. The interaction was highly significant for both OS and PFS (P=0.013 and P=0.003, respectively). This model remained significant after excluding six patients receiving doses<42 Gy (OS, P=0.024, and PFS, P=0.001).

CONCLUSIONS

The outcome for patients with LGG is dependent on extent of tumor resection and radiation dose. Patients with PR should be considered for higher radiation dose schedules (>50 Gy). Future trials on therapeutic strategies for LGG should consider stratification of patients by extent of tumor resection. Our data suggests that one dose does not fit all.

Exchange bias as a probe of the incommensurate spin-density wave in epitaxial Fe/Cr(001)

We report clear multiple period oscillations in the temperature dependence of exchange bias in an Fe thin film exchange coupled to a neighboring Cr film. The oscillations arise due to an incommensurate spin-density wave in the Cr, with wave vector perpendicular to the Fe/Cr(001) interface. The exchange bias and coercivity allow for a determination of the extent of the thermally driven wavelength expansion, the (strain-suppressed) spin-flip transition temperature, and the Cr Néel temperature, which show a crossover from bulklike to finite-size behavior at a Cr thickness of approximately 1100 A. The data are consistent with a transition from a transverse to longitudinal wave on cooling.

Evolution with composition of the d-band density of states at the Fermi level in highly spin polarized Co1-xFexS2

Highly spin polarized (SP) and half-metallic ferromagnetic systems are of considerable current interest and of potential importance for spintronic applications. Recent work has demonstrated that Co1-xFexS2 is a highly polarized ferromagnet (FM) where the spin polarization can be tuned by alloy composition. Using 59Co FM-NMR as a probe, we have measured the low-temperature spin relaxation in this system in magnetic fields from 0 to 1.0 T for 0<or=x<or=0.3. The 59Co spin-lattice relaxation rates follow a linear T dependence. Analysis of the data, using expressions for a FM system, permits information to be obtained on the d-band density of states at the Fermi level. The results are compared with independent density of states values inferred from electronic specific heat measurements and band structure calculations. It is shown that FM-NMR can be an important method for investigating highly SP systems.

Artificial ‘spin ice’ in a geometrically frustrated lattice of nanoscale ferromagnetic islands

Frustration, defined as a competition between interactions such that not all of them can be satisfied, is important in systems ranging from neural networks to structural glasses. Geometrical frustration, which arises from the topology of a well-ordered structure rather than from disorder, has recently become a topic of considerable interest. In particular, geometrical frustration among spins in magnetic materials can lead to exotic low-temperature states, including 'spin ice', in which the local moments mimic the frustration of hydrogen ion positions in frozen water. Here we report an artificial geometrically frustrated magnet based on an array of lithographically fabricated single-domain ferromagnetic islands. The islands are arranged such that the dipole interactions create a two-dimensional analogue to spin ice. Images of the magnetic moments of individual elements in this correlated system allow us to study the local accommodation of frustration. We see both ice-like short-range correlations and an absence of long-range correlations, behaviour which is strikingly similar to the low-temperature state of spin ice. These results demonstrate that artificial frustrated magnets can provide an uncharted arena in which the physics of frustration can be directly visualized.

Co1-xFexS2: a tunable source of highly spin-polarized electrons

In the emerging field of spin-electronics ideal ferromagnetic electron sources would not only possess a high degree of spin polarization, but would also offer control over the magnitude of this polarization. We demonstrate here that a simple scheme can be utilized to control both the magnitude and the sign of the spin polarization of ferromagnetic CoS2, which we probe with a variety of techniques. The position of the Fermi level is fine-tuned by solid solution alloying with the isostructural diamagnetic semiconductor FeS2, leading to tunable spin polarization of up to 85%.

Intergranular giant magnetoresistance in a spontaneously phase separated perovskite oxide

We present small-angle neutron scattering data proving that, on the insulating side of the metal-insulator transition, the doped perovskite cobaltite La(1-x)Sr(x)CoO(3) phase separates into ferromagnetic metallic clusters embedded in a nonferromagnetic matrix. This induces a hysteretic magnetoresistance, with temperature and field dependence characteristic of intergranular giant magnetoresistance (GMR). We argue that this system is a natural analog to the artificial structures fabricated by depositing nanoscale ferromagnetic particles in a metallic or insulating matrix; i.e., this material displays a GMR effect without the deliberate introduction of chemical interfaces.

Magnetic phase separation in La1-xSrxCoO3 by 59Co nuclear magnetic resonance

59Co NMR measurements on La1-xSrxCoO3 reported here establish unequivocally, for the first time, the coexistence of ferromagnetic regions, spin-glass regions, and hole-poor low spin regions at all x values from 0.1 to 0.5. A zero external field NMR spectrum, which is assigned to the ferromagnetic regions, has a spectral shape that is nearly x independent at 1.9 K, as are the relaxation times, T1 and T2. The integrated spectral area increases rapidly with x up to x = 0.2 and then decreases slightly for larger x. In a field of 9.97 T, a narrow NMR line is observed at 102 MHz, identical to that found in x = 0 samples in previous work. The integrated intensity of this spectrum decreases rapidly with increasing x, and is ascribed to hole-poor low spin regions. Beneath this spectrum, a third broad line, with a peak at 100 MHz, is assigned to a spin- or cluster-glass-like phase.

Drug treatment of scleroderma

Scleroderma or systemic sclerosis is a rare condition with many clinical manifestations including Raynaud's phenomenon. As with many other rarely encountered diseases, drug therapy for scleroderma is often empirical with little evidence in the form of randomised controlled trials to aid drug choice. Raynaud's phenomenon has been recognised for well over 100 years. A considerable number of clinical trials in this area have demonstrated unequivocally the use of nifedipine as a gold standard. Large studies have also demonstrated the efficacy of iloprost. However, this drug is not as yet licensed for scleroderma in the UK or elsewhere. This presents an additional problem as information regarding the use and administration of unlicensed drugs is often sparse and post-marketing surveillance to assess safety is not routinely performed. When looking at the other distinct conditions encountered by a patient with scleroderma it becomes evident that trials are often retrospective or limited in patient numbers. Studies investigating the use of methotrexate, antithymocyte globulin and cyclophosphamide in patients with scleroderma have been very small and in some cases not well designed. The major work on penicillamine was a retrospective trial. Again these drugs are not licensed for use in scleroderma. Drug therapy for pulmonary hypertension secondary to scleroderma closely follows that outlined for primary pulmonary hypertension. In the US there is a patient registry for primary pulmonary hypertension that has enabled well designed, large-scale studies to demonstrate the benefits of epoprostenol in severe primary pulmonary hypertension. Hence, research in this area has progressed considerably over the last decade. Clearly, a considerable amount of work is being carried out to elucidate new treatment regimens for scleroderma, however, evaluation of these studies is proving to be a difficult process. Designated hospital centres for scleroderma (there are currently 2 in the UK), better markers of disease activity and methods to measure improvement or deterioration in affected organs, should enable research into aetiology, disease progression and treatment to be carried out on a larger scale resulting, hopefully, in more conclusive answers.

Two-stage magnetization reversal in exchange biased bilayers

MnF(2)/Fe bilayers exhibit asymmetric magnetization reversal that occurs by coherent rotation on one side of the loop and by nucleation and propagation of domain walls on the other side of the loop. Here, we show by polarized neutron reflectometry, magnetization, and magnetotransport measurements that for samples with good crystalline "quality" the rotation is a two-stage process, due to coherent rotation to a stable state perpendicular to the cooling field direction. The result is remarkably asymmetrically shaped hysteresis loops.

Efficacy of the echinocandin caspofungin against disseminated aspergillosis and candidiasis in cyclophosphamide-induced immunosuppressed mice

The in vivo efficacy of the echinocandin antifungal caspofungin acetate (caspofungin; MK-0991) was evaluated in models of disseminated aspergillosis and candidiasis in mice with cyclophosphamide (CY)-induced immunosuppression. Caspofungin is a 1, 3-beta-D-glucan synthesis inhibitor efficacious against a number of clinically relevant fungi including Aspergillus and Candida species. Models of CY-induced transient or chronic leukopenia were used with once daily administration of therapy initiated 24 h after microbial challenge. Caspofungin was effective in treating disseminated aspergillosis in mice that were transiently leukopenic (significant prolongation of survival at doses of > or =0.125 mg/kg of body weight and a 50% protective dose [PD(50)] of 0.245 mg/kg/day at 28 days after challenge) or chronically leukopenic (50 to 100% survival at doses of > or =0.5 mg/kg and PD(50)s ranging from 0.173 to 0.400 mg/kg/day). Caspofungin was effective in the treatment and sterilization of Candida infections in mice with transient leukopenia with a 99% effective dose based on reduction in log(10) CFU of Candida albicans/gram of kidneys of 0.119 mg/kg and 80 to 100% of the caspofungin-treated mice having sterile kidneys at caspofungin doses from 0.25 to 2.0 mg/kg. In Candida-infected mice with chronic leukopenia, caspofungin was effective at all dose levels tested (0.25 to 1.0 mg/kg), with the log(10) CFU of C. albicans/gram of kidneys of caspofungin-treated mice being significantly lower (>99% reduction) than that of sham-treated mice from day 4 to day 28 after challenge. Also, 70 to 100% of the caspofungin-treated, chronic leukopenic mice had sterile kidneys at caspofungin doses of 0.5 to 1.0 mg/kg from day 8 to 28 after challenge. Sterilization of Candida infections by caspofungin in the absence of host leukocytes provides compelling in vivo evidence for fungicidal activity against C. albicans. Further human clinical trials with caspofungin against serious fungal infections are in progress.