"Drop in" gastroscopy outpatient clinic - experience after 9 months

<p>Abstract</p> <p>Background</p> <p>Logistics handling referrals for gastroscopy may be more time consuming than the examination itself. For the patient, "drop in" gastroscopy may reduce uncertainty, inadequate therapy and time off work.</p> <p>Methods</p> <p>After an 8-9 month run-in period we asked patients, hospital staff and GPs to fill in a questionnaire to evaluate their experience with "drop in" gastroscopy and gastroscopy by appointment, respectively. The diagnostic gain was evaluated.</p> <p>Results</p> <p>112 patients had "drop in" gastroscopy and 101 gastroscopy by appointment. The number of "drop in" patients varied between 3 and 12 per day (mean 6.5). Mean time from first GP consultation to gastroscopy was 3.6 weeks in the "drop in" group and 14 weeks in the appointment group. The half-yearly number of outpatient gastroscopies increased from 696 before introducing "drop in" to 1022 after (47% increase) and the proportion of examinations with pathological findings increased from 42% to 58%. Patients and GPs expressed great satisfaction with "drop in". Hospital staff also acclaimed although it caused more unpredictable working days with no additional staff.</p> <p>Conclusions</p> <p>"Drop in" gastroscopy was introduced without increase in staff. The observed increase in gastroscopies was paralleled by a similar increase in pathological findings without any apparent disadvantages for other groups of patients. This should legitimise "drop in" outpatient gastroscopies, but it requires meticulous observation of possible unwanted effects when implemented.</p

Accurate ab initio spin densities

We present an approach for the calculation of spin density distributions for molecules that require very large active spaces for a qualitatively correct description of their electronic structure. Our approach is based on the density-matrix renormalization group (DMRG) algorithm to calculate the spin density matrix elements as basic quantity for the spatially resolved spin density distribution. The spin density matrix elements are directly determined from the second-quantized elementary operators optimized by the DMRG algorithm. As an analytic convergence criterion for the spin density distribution, we employ our recently developed sampling-reconstruction scheme [J. Chem. Phys. 2011, 134, 224101] to build an accurate complete-active-space configuration-interaction (CASCI) wave function from the optimized matrix product states. The spin density matrix elements can then also be determined as an expectation value employing the reconstructed wave function expansion. Furthermore, the explicit reconstruction of a CASCI-type wave function provides insights into chemically interesting features of the molecule under study such as the distribution of $\alpha$- and $\beta$-electrons in terms of Slater determinants, CI coefficients, and natural orbitals. The methodology is applied to an iron nitrosyl complex which we have identified as a challenging system for standard approaches [J. Chem. Theory Comput. 2011, 7, 2740].Comment: 37 pages, 13 figure

Dominance of Objects over Context in a Mediotemporal Lobe Model of Schizophrenia

Background: A large body of evidence suggests impaired context processing in schizophrenia. Here we propose that this impairment arises from defective integration of mediotemporal ‘what ’ and ‘where ’ routes, carrying object and spatial information to the hippocampus. Methodology and Findings: We have previously shown, in a mediotemporal lobe (MTL) model, that the abnormal connectivity between MTL regions observed in schizophrenia can explain the episodic memory deficits associated with the disorder. Here we show that the same neuropathology leads to several context processing deficits observed in patients with schizophrenia: 1) failure to choose subordinate stimuli over dominant ones when the former fit the context, 2) decreased contextual constraints in memory retrieval, as reflected in increased false alarm rates and 3) impaired retrieval of contextual information in source monitoring. Model analyses show that these deficits occur because the ‘schizophrenic MTL ’ forms fragmented episodic representations, in which objects are overrepresented at the expense of spatial contextual information. Conclusions and Significance: These findings highlight the importance of MTL neuropathology in schizophrenia, demonstrating that it may underlie a broad spectrum of deficits, including context processing and memory impairments. It is argued that these processing deficits may contribute to central schizophrenia symptoms such as contextuall

Flexible photonic crystal membranes with nanoparticle high refractive index layers

Flexible photonic crystal slabs with an area of 2 cm2 are fabricated by nanoimprint replication of a 400 nm period linear grating nanostructure into a ≈60 µm thick polydimethylsiloxane membrane and subsequent spin coating of a high refractive index titanium dioxide nanoparticle layer. Samples are prepared with different nanoparticle concentrations. Guided-mode resonances with a quality factor of Q ≈ 40 are observed. The highly flexible nature of the membranes allows for stretching of up to 20% elongation. Resonance peak positions for unstretched samples vary from 555 to 630 nm depending on the particle concentration. Stretching results in a resonance shift for these peaks of up to ≈80 nm, i.e., 3.9 nm per % strain. The color impression of the samples observed with crossed-polarization filters changes from the green to the red regime. The high tunability renders these membranes promising for both tunable optical devices as well as visualization devices