Ultra-soft X-ray system for imaging the early cellular responses to X-ray induced DNA damage.

The majority of the proteins involved in processing of DNA double-strand breaks (DSBs) accumulate at the damage sites. Real-time imaging and analysis of these processes, triggered by the so-called microirradiation using UV lasers or heavy particle beams, yielded valuable insights into the underlying DSB repair mechanisms. To study the temporal organization of DSB repair responses triggered by a more clinically-relevant DNA damaging agent, we developed a system coined X-ray multi-microbeam microscope (XM3), capable of simultaneous high dose-rate (micro)irradiation of large numbers of cells with ultra-soft X-rays and imaging of the ensuing cellular responses.

How does injury compensation affect health and disability in patients with complaints of whiplash? A qualitative study among rehabilitation experts-professionals.

Purpose: To explore rehabilitation professionals' opinions about the influence and the pathways of injury compensation (IC) on health and disability in patients with whiplash associated disorder (WAD).

Methods: Semi-structured interviews were performed among a purposeful selected sample of Dutch expert-professionals in the field of rehabilitation of patients with WAD. Inclusion continued until saturation was reached.

The association of clinical and microbiologic parameters with histologic observations in relatively healthy peri-implant conditions- a preliminary short-term in vivo study.

Purpose: To determine whether clinical findings-bleeding on probing, pocket depth, recession, and bacterial sampling-correlate with histologic outcomes in relatively healthy peri-implant soft tissues in people.

Materials And Methods: In this cross-sectional study, a convenience sample of 20 edentulous subjects received two endosseous mandibular implants each. The abutments were either zirconia (ZrO₂) or titanium (Ti) (nonsubmerged implant placement, within-subject comparison, leftright randomization).

Relationship between self-reported disability and functional capacity in patients with whiplash associated disorder.

Purpose: Patients with chronic Whiplash Associated Disorders (WAD) report symptoms and disability. Neither the relationship between self-reported disability and functional capacity, nor its predictors have been investigated in patients with WAD. This was the purpose of this study.

Which instruments can detect submaximal physical and functional capacity in patients with chronic nonspecific back pain? A systematic review.

Study Design: Systematic review.

Objective: To evaluate the validity of instruments that claim to detect submaximal capacity when maximal capacity is requested in patients with chronic nonspecific musculoskeletal pain.

Summary Of Background Data: Several instruments have been developed to measure capacity in patients with chronic pain.

Structural properties of subnanometer thick Y layers in extreme ultraviolet multilayer mirrors.

We studied the structure and optical properties of B(4)C/Mo/Y/Si multilayer systems. Using extended x-ray absorption fine structure measurements at the Y and Mo K-edge, the structure of the subnanometer thick Y layer and the underlying Mo layer were analyzed. It was found that even a 0.

Soft tissue response to zirconia and titanium implant abutments: an in vivo within-subject comparison.

Aim: To compare the health of the soft tissues towards zirconia and titanium abutments in man, as observed using histological data.

Material And Methods: Twenty patients received two mandibular implants with either a zirconia or titanium abutment (split mouth study design, left-right randomization). After 3 months soft tissue biopsies were prepared for histological evaluation.

Early bacterial colonization and soft tissue health around zirconia and titanium abutments: an in vivo study in man.

Aim: To compare the early bacterial colonization and soft tissue health of mucosa adjacent to zirconia (ZrO(2)) and titanium (Ti) abutment surfaces in vivo.

Materials And Methods: Twenty edentulous subjects received two endosseous mandibular implants. The implants were fitted with either a ZrO(2) or a Ti abutment (non-submerged implant placement, within-subject comparison, left-right randomization).

Radiographic features of mandibular trabecular bone structure in hypodontia.

Purpose: Radiographic parameters of mandibular trabecular bone structure between 67 subjects having hypodontia and those without were studied on digital panoramic radiographs.

Materials And Methods: Three regions of interest (ROI) were defined: the ascending ramus, apical of the mandibular molar and mesial of the first mandibular molar. The effects of the presence of hypodontia and the ROI on the mandibular trabecular bone structure were tested for statistical significance by means of multivariate analysis.

Dental implants in persons with severe epilepsy and multiple disabilities: a long-term retrospective study.

Purpose: A retrospective study on the performance of endosseous implants in a population of patients with severe epilepsy and additional motor and/or intellectual impairments was performed.

Materials And Methods: All residents of an inpatient center for persons affected by severe, refractory epilepsy and multiple disabilities who received endosseous implants between 1991 and April 2007 were included in the study. Implant survival was analyzed using the Kaplan-Meier method.

An ultrasoft X-ray multi-microbeam irradiation system for studies of DNA damage responses by fixed- and live-cell fluorescence microscopy.

Localized induction of DNA damage is a valuable tool for studying cellular DNA damage responses. In recent decades, methods have been developed to generate DNA damage using radiation of various types, including photons and charged particles. Here we describe a simple ultrasoft X-ray multi-microbeam system for high dose-rate, localized induction of DNA strand breaks in cells at spatially and geometrically adjustable sites.

Bone structure changes in iliac crest grafts combined with implants.

Background: Remodeling of onlay grafts combined with implants to the mandible results in predictable changes in the graft's radiographic density. We studied the relationship between changes in radiographic density and trabecular structure during the first year after onlay grafting with simultaneous implant placement to the mandible.

Purpose: The aim of this study was to evaluate changes in bone structure after onlay grafting.

Comment: Electron-transfer reactions in the 9-mesityl-10-methylacridinium ion: impurities, triplet states and infinitely long-lived charge-shift states?

The likelihood of an infinitely long-lived, charge-shift state being formed by the target compound is re-assessed in light of persistent claims that such chemistry is both viable and observable.

Ultrafast intersystem crossing in 9,10-anthraquinones and intramolecular charge separation in an anthraquinone-based dyad.

Femtosecond transient absorption spectroscopy was employed to determine quantitatively the ultrafast S1-T1 intersystem crossing in a 2-substituted 9,10-anthraquinone derivative (3), kisc = 2.5 x 10(12) s-1. Notwithstanding this rapid process, photoexcitation of dyad 1 is followed by competition between intersystem crossing and intramolecular charge separation, the latter leading to a short-lived (2 ps) singlet charge-transfer (CT) state.

Permucosal implants combined with iliac crest onlay grafts used in extreme atrophy of the mandible: long-term results of a prospective study.

Thirteen patients received an onlay bone-graft augmentation to their severely atrophic mandible in combination with simultaneous implant insertion. This treatment modality was studied in a long-term prospective clinical and radiographic study. A reproducible measurement method, consisting of oblique lateral cephalometric radiographs, in combination with an image analysis system, was used to accurately assess the graft resorption rate.

Charge shift and triplet state formation in the 9-mesityl-10-methylacridinium cation.

The target donor-acceptor compound forms an acridinium-like, locally excited (LE) singlet state on illumination with blue or near-UV light. This LE state undergoes rapid charge transfer from the acridinium ion to the orthogonally sited mesityl group in polar solution. The resultant charge-transfer (CT) state fluoresces in modest yield and decays on the nanosecond time scale.

Long-lived charge-transfer states in compact donor-acceptor dyads.

Photoinduced electron transfer is a widely applied method to convert photon energy into a useful (electro)chemical potential, both in nature and in artificial devices. There is a continuing effort to develop molecular systems in which the charge-transfer state, populated by photoinduced electron transfer, survives sufficiently long to tap the energy stored in it. In general this has been found to require the construction of rather complex molecular systems, but more recently a few approaches have been reported that allow the use of much more simple and relatively small electron donor-acceptor dyads for this purpose.

Illumination of the 9-mesityl-10-methylacridinium ion does not give a long-lived photoredox state.

Photolysis of the 9-mesityl-10-methylacridinium cation in benzonitrile forms an acridinyl radical, detected by EPR and UV-visible spectroscopy, by way of a sacrificial process.

Electron transfer at the single-molecule level in a triphenylamine-perylene imide molecule.

Photoinduced electron transfer (ET) processes in a donor-acceptor system based on triphenylamine and perylene imide have been studied at the single-molecule (SM) and ensemble levels. The system exists as two isomers, one of which undergoes forward and reverse ET in toluene with decay constants of 3.0 and 2.

Probing conformational dynamics in single donor-acceptor synthetic molecules by means of photoinduced reversible electron transfer.

We use single-molecule fluorescence lifetimes to probe dynamics of photoinduced reversible electron transfer occurring between triphenylamine (donor) and perylenediimide (acceptor) in single molecules of a polyphenylenic rigid dendrimer embedded in polystyrene. Here, reversible electron transfer in individual donor-acceptor molecules results in delayed fluorescence that is emitted with a high photon count rate. By monitoring fluorescence decay times on a photon-by-photon basis, we find fluctuations in both forward and reverse electron transfer spanning a broad time range, from milliseconds to seconds.

A prospective evaluation of Frialoc implants with ball-abutments in the edentulous mandible: 1-year results.

Several surgical and prosthetic concepts for the treatment of patients with mandibular atrophy and related lower denture problems are proposed and described in the literature. The present study discusses and evaluates the use of a new single-stage implant and overdenture with ball-attachment for this purpose. This study evaluates the clinical performance of the implants and abutments and addresses surgical and prosthetic complications that were encountered.

Characterization by time-resolved UV-Vis and infrared absorption spectroscopy of an intramolecular charge-transfer state in an organic electron-donor-bridge-acceptor system.

A long-lived intramolecular charge-separated state in an electron-donor-acceptor molecule is characterized by time-resolved visible and infrared absorption spectroscopy. Bands that can be assigned to the negatively charged acceptor chromophore can be clearly observed in the time-resolved IR spectrum. In contrast, the electronic absorption spectrum of the radical anion lacks characteristic absorption bands.

Decay pathways of charge-separated states in strongly fluorescent electron donor-acceptor compounds.

The nonradiative decay pathways are studied of the 1-cyano-4-cyclohexylidenenaphthalene chromophore and electron donor acceptor compounds containing the same chromophore. It is argued that the rapid decay at room temperature of the locally excited singlet state of the electron acceptor chromophore involves twisting of the double bond via a low barrier, and a polar transition state. In non-polar solvents the charge transfer excited states also decay mostly via a thermally activated decay process, possibly via a similar pathway as the locally excited state of the acceptor unit.

Spin control of the lifetime of an intramolecular charge-transfer excited state.

Triplet-sensitized generation of a long-lived intramolecular charge-separated excited state is described in an electron donor-acceptor molecule with a short distance between the donor and the acceptor. Time-resolved UV-Vis optical absorption spectroscopy shows that the lifetime of this triplet excited state is 1.4 micros in acetonitrile at 298 K, i.