Population grid-based assessment of the impact of broadband expansion on population development in rural areas.

This paper estimates the effect of the expansion of broadband infrastructure, which enables high-speed Internet, on population development in panel of Finnish areas in the period 2010-2018. The study differs from previous studies in that it uses accurate statistics on the availability of broadband in 1 km * 1 km population grids. Therefore, the impact of broadband availability on rural development is evaluated more accurately than previously. The results of the Difference-in-difference (DiD) regression analysis show that the availability of broadband reduces depopulation of remote and sparsely populated rural areas. In this respect, the telecommunication policy in Finland has been successful, and the findings encourage the expansion of broadband infrastructure in rural areas.

Double Jahn-Teller Distortion in AuGe Complexes Leading to a Dual Blue-Orange Emission.

Invited for this month's cover are collaborators from the group of José M. López-de-Luzuriaga at Universidad de la Rioja, Spain and researchers from University of Helsinki, Finland. The cover picture shows a photograph of a gold-germanium complex that has two emission modes corresponding to two independent triplet excited states. Read the full text of the article at 10.1002/cplu.201500337.

Double Jahn-Teller Distortion in AuGe Complexes Leading to a Dual Blue-Orange Emission.

The tetrahedral AuI complexes [Au(GeCl3 )L3 ] (L=PMe3  (1), PMe2 Ph (2), PMePh2  (3), PPh3  (4)) were synthesized by in situ treatment of the [Au(GeCl3 )(tht)] complex with three equivalents of the corresponding tertiary phosphine. The crystal structures of complexes 1 and 3 have been determined through X-ray diffraction studies and show [GeCl3 ]- fragments bonded to the corresponding [Au(PR3 )3 ]+ units through covalent bonds, leading to a tetrahedral coordination environment for gold. Complexes 3 and 4 show dual phosphorescence in the solid state at 77 K and, in the case of complex 4, an interesting room-temperature mechanochromism effect is observed. Correlated MP2, SCS-MP2, SCS-CC2, and ONIOM MP2/UFF calculations suggest the existence of two largely distorted and thermally connected triplet excited states (T1 and T2 ) for a model system of complex 4. The AuP3 + moiety can be distorted in two different planes leading to the two triplet excited states T1 and T2 , leaving the GeCl3 - unit almost unaltered. The emissions of these phosphorescent AuI GeII complexes is mainly ascribed to a metal (gold)-centered (3 MC) transition with some contribution from the [GeCl3 ]- fragments.

Structural and photophysical study on heterobimetallic complexes with d8-d10 interactions supported by carborane ligands: theoretical analysis of the emissive behaviour.

Heterobimetallic complexes of formula [M{(PPh2)2C2B9H10}(S2C2B10 H10)M'(PPh3)] (M=Pd, Pt; M'=Au, Ag, Cu) and [Ni{(PPh2)2C2B9H10}(S2C2B10H10)Au(PPh3)] were obtained from the reaction of [M{(PPh2)2C2B10H10}(S2C2B10H10)] (M=Pd, Pt) with [M'(PPh3)](+) (M'=Au, Ag, Cu) or by one-pot synthesis from [(SH2C2B10H10], (PPh2 )2C2B10H10, NiCl2 ⋅6 H2 O, and [Au(PPh3)](+). They display d(8)-d(10) intermetallic interactions and emit red light in the solid state at 77 K. Theoretical studies on [M{(PPh2)2C2B9H10}(S2C2B10H10)Au(PPh3)] (M=Pd, Pt, Ni) attribute the luminescence to ligand (thiolate, L)-to-"P2-M-S2" (ML') charge-transfer (LML'CT) transitions for M=Pt and to metal (M)-to-"P2-M-S2" (ML') charge-transfer (MML'CT) transitions for M=Ni, Pd.

Double Photoinduced Jahn-Teller Distortion of Tetrahedral AuI SnII Complexes.

Tetrahedral AuI complexes [L3 Au(SnCl3 )] (L=PMe3 (1), PMe2 Ph (2), PMePh2 (3), and PPh3 (4)) were prepared by treatment of the [(tht)Au(SnCl3 )] (tht=tetrahydrothiophene) complex with three equivalents of the corresponding tertiary phosphine. The crystal structures of complexes 1-4 have been determined through X-ray diffraction studies showing, in all cases, [SnCl3 ]- fragments covalently bonded to the corresponding [Au(PR3 )3 ]+ units, which leads to a tetrahedral coordination environment for gold. Complexes 3 and 4 show phosphorescence in the solid state at room temperature and 77 K that is largely redshifted relative to the free [Au(PR3 )3 ]+ and [SnCl3 ]- counterparts. Correlated MP2, SCS-MP2, and ONIOM MP2/UFF calculations suggest a largely distorted lower triplet excited state (T1 ) for each model system. The AuP3 + moiety is distorted leading to a T-shape, whereas the SnCl3 - unit is left almost unaltered. Molecular orbital and population analysis suggest that the emission of these tetrahedral AuI complexes arises from a 3 MC transition slightly perturbed by the SnCl3 - fragment.

The gauge including magnetically induced current method.

An overview of applications of the recently developed gauge including magnetically induced current method (GIMIC) is presented. The GIMIC method is used to obtain magnetically induced current densities in molecules. It provides detailed information about electron delocalization, aromatic character, and current pathways in molecules. The method has been employed in aromaticity studies on hydrocarbons, complex multi-ring organic nanorings, Möbius twisted molecules, inorganic and all-metal molecular rings and open-shell species. Recent studies on hydrogen-bonded molecules indicate that GIMIC can also be used to estimate hydrogen-bond strengths without fragmentation of the system. Preliminary results are presented on the applicability of GIMIC for investigating current transport in molecules attached to clusters simulating molecular conductivity measurements. Advantages and limitations of the GIMIC method are reviewed and discussed.

Hydrogen-bond strengths by magnetically induced currents.

We present here a "non-invasive" computational method to estimate the strength of individual hydrogen bonds using magnetically induced currents. The method is calibrated using H-bonding dimers, and applied on Watson-Crick DNA base pairs and proton wires in carbonic anhydrase.

Coupled-cluster and density functional theory studies of the electronic excitation spectra of trans-1,3-butadiene and trans-2-propeniminium.

The electronic excitation spectra of trans-1,3-butadiene (CH(2)=CH-CH=CH(2)) and trans-2-propeniminium (CH(2)=CH-CH=NH(2)(+)) have been studied at several coupled-cluster and time-dependent density functional theory levels using the linear response approach. Systematic studies employing large correlation-consistent basis sets show that approximate singles and doubles coupled-cluster calculations yield excitation energies in good agreement with experiment for all states except for the two lowest excited A(g) states of trans-1,3-butadiene which have significant multiconfigurational character. Time-dependent density functional theory calculations employing the generalized gradient approximation and hybrid functionals yield too low excitation energies in the basis set limit. In trans-1,3-butadiene, increasing the basis set size by augmenting multiple diffuse functions is observed to reduce the high-lying excitation energies with most density functionals. The decrease in the energies is connected to the incorrect asymptotic behavior of the exchange-correlation potential. The results also demonstrate that standard density functionals are not capable of providing excitation energies of sufficient accuracy for experimental assignments.

Computational studies of semiconductor quantum dots.

Light-absorption and luminescence processes in nano-sized materials can be modelled either by using computational approaches developed for quantum chemical calculations or by applying computational methods in the effective mass approximation (EMA) originally intended for solid-state theory studies. An overview of the theory and implementation of an ab initio correlation EMA method for studies of luminescence properties of embedded semiconductor quantum dots is presented. The applicability of the method and the importance of correlation effects are demonstrated by calculations on InGaAs/GaAs quantum-dot and quantum-ring samples. Ab initio and density functional theory (DFT) quantum chemical studies of optical transitions in freestanding silicon nanoclusters are also discussed. The accuracy of the optical gaps and oscillator strengths for silicon nanoclusters obtained using different computational methods is addressed. Changes in the cluster structures, excitation energies and band strengths upon excitation are reported. The role of the surface termination and functional groups on the silicon nanocluster surfaces is discussed.

Coupled-cluster studies of the electronic excitation spectra of silanes.

The electronic excitation spectra of unsubstituted linear silanes (n-Si(m)H(2m+2), m = 1-6), cyclopentasilane (c-Si5H10), and neopentasilane (neo-Si5H12) have been studied at the coupled-cluster approximate singles and doubles (CC2) level using Dunning's quadruple-zeta basis sets augmented with diffuse functions (aug-cc-pVQZ). Comparisons with measured ultraviolet spectra for Si2H6 and n-Si3H8 show that CC2 calculations using these basis sets yield excitation energies in good agreement with experiment. The calculated excitation thresholds for Si2H6 and n-Si3H8 of 7.61 and 6.68 eV are only 0.05 eV larger than the gas-phase values of 7.56 and 6.63 eV, respectively. For n-Si4H10, n-Si5H12, and neo-Si5H12, the calculated excitation thresholds of 6.51, 6.14, and 6.87 eV for the lowest dipole-allowed transitions are about 0.4 eV larger than the corresponding liquid-phase data of 6.05, 5.77, and 6.53 eV; the discrepancy can mainly be attributed to solvent effects. The obtained excitation thresholds for n-Si6H14 is 5.85 eV, whereas no experimental data are available for its optical gap. Calculations using the Karlsruhe triple-zeta valence basis sets augmented with single and double sets of polarization functions show that very large basis sets augmented with diffuse functions are needed for obtaining accurate excitation energies. The optical gaps for silanes obtained using the triple-zeta polarization basis sets were found to be 0.4 and 0.2 eV larger than those obtained using Dunning's quadruple-zeta basis sets. Excitation thresholds calculated at density functional theory levels using generalized gradient approximation are 0.7-1.0 eV smaller than the experimental values and by employing hybrid functionals they are 0.3-0.4 eV below the experimental thresholds. By adding the present basis-set correction and environmental effects to the previously calculated CC2 value for the excitation threshold of the Si29H36 silicon nanocluster, the extrapolated absorption threshold is 4.0 eV as compared to the recently reported experimental value of 3.7 eV.

Bright luminescence from silane substituted and bridged silicon nanoclusters.

Time-dependent density functional theory (TDDFT) calculations show that silicon nanoclusters (Si-NC) capped by linear silane groups have large oscillator strengths of the same magnitude as reported in recent experimental studies. We propose a mechanism where linear silanes attached to the Si-NC surface affect the optical properties enhancing the oscillator strengths and thereby accounting for the bright luminescence observed in the blue region of the visible spectrum. The anisotropic emission seen experimentally can also be explained by the presence of the silane groups on the cluster surface. The excitation energies are found to be only slightly affected by the silanes, whereas the oscillator strengths increase with the length of the silane chain and are significantly larger than obtained for unsubstituted Si-NCs. In TDDFT studies of Si-NC dimers interconnected by a linear silane bridge, we obtained large oscillator strengths indicating that such structures could be useful light sources for optical devices.

Stochastic boundary molecular dynamics simulation of L-ribose in the active site of Actinoplanes missouriensis xylose isomerase and its Val135Asn mutant with improved reaction rate.

We used molecular dynamics simulations to study how a non-natural substrate, L-ribose, interacts with the active site of Actinoplanes missouriensis xylose isomerase. The simulations showed that L-ribose does not stay liganded in the active site in the same way as D-xylose, in which the oxygens O2 and O4 are liganded to the metal M1. The oxygen O4 of L-ribose moved away from the metal M1 to an upside down position. Furthermore, the distances of the carbons C1 and C2 of L-ribose to the catalytic metal M2 were higher than in the case of D-xylose. These findings explain the extremely low reaction rate of xylose isomerase with L-ribose. The mutation V135N close to the C5-OH of the substrate increased the reaction efficiency 2- to 4-fold with L-ribose. V135N did not affect the reaction with D-xylose and L-arabinose, whereas the reaction with D-glucose was impaired, probably due to a hydrogen bond between Asn-135 and the substrate. When L-ribose was the substrate, Asn-135 formed a hydrogen bond to Glu-181. As a consequence, O4 of L-ribose stayed liganded to the metal M1 in the V135N mutant in molecular dynamics simulations. This explains the decreased K(m) of the V135N mutant with L-ribose.

Elimination of epidemic methicillin-resistant Staphylococcus aureus from a university hospital and district institutions, Finland.

From August 1991 to October 1992, two successive outbreaks of methicillin-resistant Staphylococcus aureus (MRSA) occurred at a hospital in Finland. During and after these outbreaks, MRSA was diagnosed in 202 persons in our medical district; >100 cases involved epidemic MRSA. When control policies failed to stop the epidemic, more aggressive measures were taken, including continuous staff education, contact isolation for MRSA-positive patients, systematic screening for persons exposed to MRSA, cohort nursing of MRSA-positive and MRSA-exposed patients in epidemic situations, and perception of the 30 medical institutions in that district as one epidemiologic entity brought under surveillance and control of the infection control team of Turku University Hospital. Two major epidemic strains, as well as eight additional strains, were eliminated; we were also able to prevent nosocomial spread of other MRSA strains. Our data show that controlling MRSA is possible if strict measures are taken before the organism becomes endemic. Similar control policies may be successful for dealing with new strains of multiresistant bacteria, such as vancomycin-resistant strains of S. aureus.

Population density and occurrence of accidents in Finland.

INTRODUCTION: About one million accidents occur yearly in Finland (population 5.2 million), resulting in over 3,000 deaths, annually. The governmental and municipal authorities are responsible for the healthcare services that respond to these accidents. So far, resources for these services have been allocated according to regional equality, or in some cases, on the basis of population numbers. However, economical and effective resource allocation should be based on detailed risk analysis of the accidents. HYPOTHESIS: In areas with more dense populations, the level of social activity is greater, which leads to an increased risk for accidents (traffic, civil disturbance, etc.). METHODS: The number of accidents was estimated on the basis of registered emergency trauma patients using the Finnish healthcare statistics for the year 1999. The emergency visits were compared to the populations and populations' densities of the regional sub-units. The rate of emergency injuries was analysed by regression analysis according to varying population density in Finland. RESULTS: The number of accidents per inhabitants was related directly to population density. There was a correlation between emergency visits per inhabitant and population density (p < 0.0001). According to estimates, each 1% increase in population density is associated with a 0.4% increase in the risk of accidents. CONCLUSION: The relationship between population density and rate of emergency visits is decisive for the planning of emergency services. Services should be placed in areas of high population densities where there are more people with greater risk of accidents.