Role of quantum chemical calculations in molecular biophysics with a historical perspective

We discuss how the basic principles of quantum chemistry and quantum mechanics can be and have been applied to a variety of problems in molecular biophysics. First, the historical development of quantum concepts in biophysics is discussed. Next, we describe a series of interesting applications of quantum chemical methods for studying biologically active molecules, molecular structures, and some of the important processes which play a role in living organisms. We discuss the application of quantum chemistry to such processes as energy storage and transformation, and the transmission of genetic information. Quantum chemical approaches are essential to comprehend and understand the molecular nature of these processes. To conclude our work, we present a short discussion of the perspectives of quantum chemical methods in modern biophysics, the field of experimental and theoretical chiral vibrational and electronic spectroscopy

Equilibrium shape and dislocation nucleation in strained epitaxial nanoislands

We study numerically the equilibrium shapes, shape transitions and dislocation nucleation of small strained epitaxial islands with a two-dimensional atomistic model, using simple interatomic pair potentials. We first map out the phase diagram for the equilibrium island shapes as a function of island size (up to N = 105 atoms) and lattice misfit with the substrate and show that nanoscopic islands have four generic equilibrium shapes, in contrast with predictions from the continuum theory of elasticity. For increasing substrate-adsorbate attraction, we find islands that form on top of a finite wetting layer as observed in Stranski-Krastanow growth. We also investigate energy barriers and transition paths for transitions between different shapes of the islands and for dislocation nucleation in initially coherent islands. In particular, we find that dislocations nucleate spontaneously at the edges of the adsorbate-substrate interface above a critical size or lattice misfit.Comment: 4 pages, 3 figures, uses wrapfig.sty and epsfig.st

A combined tactile and Raman probe for tissue characterization - Design considerations

Histopathology is the golden standard for cancer diagnosis and involves the characterization of tissue components. It is labour intensive and time consuming. We have earlier proposed a combined fibre-optic near-infrared Raman spectroscopy (NIR-RS) and tactile resonance method (TRM) probe for detecting positive surgical margins as a complement to interoperative histopathology. The aims of this study were to investigate the effects of attaching an RS probe inside a cylindrical TRM sensor and to investigate how laser-induced heating of the fibre-optic NIR-RS affected the temperature of the RS probe tip and an encasing TRM sensor. In addition, the possibility to perform fibre-optic NIR-RS in a well-lit environment was investigated. A small amount of rubber latex was preferable for attaching the thin RS probe inside the TRM sensor. The temperature rise of the TRM sensor due to a fibre-optic NIR-RS at 270 mW during 20 s was less than 2 degrees C. Fibre-optic NIR-RS was feasible in a dimmed bright environment using a small light shield and automatic subtraction of a pre-recorded contaminant spectrum. The results are promising for a combined probe for tissue characterization

Tibial Fractures in Alpine Skiing and Snowboarding in Finland : A Retrospective Study on Fracture Types and Injury Mechanisms in 363 Patients

Background and Aim: Alpine skiing and snowboarding share the hazards of accidents accounting for tibial fractures. The aim of this study was to evaluate the fracture patterns and mechanisms of injury of tibial fractures taking place in downhill skiing and snowboarding. Materials and methods: All patients with tibial fracture due to alpine skiing or snowboarding accident treated in four trauma centers next to the largest ski resorts in Finland were analyzed between 2006 and 2012. The hospital records were retrospectively reviewed for data collection: equipment used (skis or snowboard), age, gender, and mechanism of injury. Fractures were classified according to AO-classification. Results: There were 342 skiing and 30 snowboarding related tibial fractures in 363 patients. Tibial shaft fracture was the most common fracture among skiers (n=215, 63%), followed by proximal tibial fractures (n=92, 27%). Snowboarders were most likely to suffer from proximal tibial fracture (13, 43%) or tibial shaft fracture (11, 37%). Snowboarders were also more likely than skiers to suffer complex AO type C fractures (23% vs 9%, p Conclusion: The most important finding was the relatively high number of the tibial plateau fractures among adult skiers. The fracture patterns between snowboarding and skiing were different; the most common fracture type in skiers was spiral tibial shaft fracture compared to proximal tibial fractures in snowboarders. Children had more simple fractures than adults.Peer reviewe

One in Three of Pediatric Tibia Shaft Fractures is Currently Treated Operatively : A 6-Year Epidemiological Study in two University Hospitals in Finland Treatment of Pediatric Tibia Shaft Fractures

Background: Internal fixation of pediatric tibia shaft fractures has become increasingly popular despite the fact that non-operative treatment results in satisfactory outcome with few exceptions. Indications for surgery and benefits of internal fixation are however still debatable. Materials and Methods: All 296 less than 16-year-old patients treated for a tibia shaft fracture between 2010 and 2015 in two of the five university hospitals in Finland were included in the study. Patient data were analyzed in three treatment groups: cast immobilization in emergency department, manipulation under anesthesia, and operative treatment. Incidence of operative treatment of pediatric tibia shaft fractures was calculated in the cities of Helsinki and Kuopio. Results: A total of 143 (47.3%) children's tibia shaft fractures were treated with casting in emergency department, 71 (22.3%) with manipulation under anesthesia, and 82 (30.4%) with surgery. Mean age of the patients in these treatment groups was 6.2, 8.7, and 12.7 years. Fibula was intact in 89%, 51%, and 27% of the patients, respectively. All 6 patients with multiple fractures and 16 of 18 patients with open fractures were treated operatively. In eight patients, primary non-operative treatment was converted to internal fixation. Operatively treated patients with isolated closed fractures were more likely to have a fibula fracture (46/66 vs 52/214, p <0.001), be older in age (13.08 2.4 vs 6.4 +/- 3.7, p <0.001), and have more primary angulation (6.9 +/- 5.8 vs 0.48 +/- 3.1, p <0.001). Re-operations were done to eight and corrective osteotomy to two operatively treated children. Conclusion: Operative treatment of a pediatric tibia shaft fracture is currently nearly a rule in patients with open or multiple fractures. Surgical treatment of closed tibia shaft fractures is based on surgeon's personal preference, type of fracture and age of the patient.Peer reviewe

Direct observation of mono-vacancy and self-interstitial recovery in tungsten

Reliable and accurate knowledge of the physical properties of elementary point defects is crucial for predictive modeling of the evolution of radiation damage in materials employed in harsh conditions. We have applied positron annihilation spectroscopy to directly detect mono-vacancy defects created in tungsten through particle irradiation at cryogenic temperatures, as well as their recovery kinetics. We find that efficient self-healing of the primary damage takes place through Frenkel pair recombination already at 35 K, in line with an upper bound of 0.1 eV for the migration barrier of self-interstitials. Further self-interstitial migration is observed above 50 K with activation energies in the range of 0.12-0.42 eV through the release of the self-interstitial atoms from impurities and structural defects and following recombination with mono-vacancies. Mono-vacancy migration is activated at around 550 K with a migration barrier of E-m(V) = 1.85 +/- 0.05 eV. (C) 2019 Author(s).Peer reviewe