Coupled Sublattice Melting and Charge-Order Transition in Two Dimensions.

Two-dimensional melting is one of the most fascinating and poorly understood phase transitions in nature. Theoretical investigations often point to a two-step melting scenario involving unbinding of topological defects at two distinct temperatures. Here, we report on a novel melting transition of a charge-ordered K-Sn alloy monolayer on a silicon substrate. Melting starts with short-range positional fluctuations in the K sublattice while maintaining long-range order, followed by longer-range K diffusion over small domains, and ultimately resulting in a molten sublattice. Concomitantly, the charge order of the Sn host lattice collapses in a multistep process with both displacive and order-disorder transition characteristics. Our combined experimental and theoretical analysis provides a rare insight into the atomistic processes of a multistep melting transition of a two-dimensional materials system.

Description, characterization, and evaluation of an online social networking community: the American Cancer Society's Cancer Survivors Network®.

PURPOSE: To describe (a) the conceptualization, purpose, and features of The American Cancer Society's Cancer Survivors Network® (CSN; http://csn.cancer.org ), (b) the ongoing two-phase evaluation process of CSN, and (c) the characteristics of CSN members. METHODS: An online opt-in self-report survey of CSN members (N = 4762) was conducted and digital metrics of site use were collected. RESULTS: Annually, CSN attracts over 3.6 million unique users from over 200 countries/territories. Most commonly used site features are discussion boards (81.1%), the search function (63.8%), and the member resource library (50.2%). The survey sample is mostly female (69.6%), non-Hispanic white (84.1%), and self-identified as a cancer survivor (49.8%), or both cancer survivor and cancer caregiver (31.9%). A larger number of survey respondents reported head and neck cancer (12.5%), relative to cancer incidence/prevalence data. CONCLUSIONS: The volume of CSN traffic suggests high demand among cancer survivors and caregivers for informational and/or emotional support from other cancer survivors and caregivers. CSN may be particularly beneficial for individuals with rare cancers. Furthermore, this study documents a group of individuals whose cancer experience is multifaceted (e.g., survivors became caregivers or vice versa), and for whom CSN has the capacity to provide support at multiple points during their cancer experiences. IMPLICATIONS FOR CANCER SURVIVORS: CSN is a free, internet-based social networking site available to all cancer survivors and caregivers, worldwide. Evaluation of the site is ongoing and will be used to inform improvements to usability, reach, recruitment, retention, and potential health impact(s) of this valuable resource.

Prevalence of exon 11 internal tandem duplications in the C-KIT proto-oncogene in Australian canine mast cell tumours.

OBJECTIVE: To measure the prevalence of internal tandem duplications (ITDs) in exon 11 of the proto-oncogene C-KIT in a sample of Australian cutaneous canine mast cell tumours (MCTs) drawn from general practice and to evaluate relationships between tumour mutation status and prognostic factors including signalment, tumour histological grade, tumour anatomical location and tumour size. METHODS: C-KIT exon 11 ITDs were detected by PCR in DNA extracted from formalin-fixed, paraffin-embedded canine MCTs sourced from three veterinary diagnostic laboratories in Adelaide and Melbourne. Tumours were graded according to two different systems (Patnaik and Kiupel systems) by board-certified anatomical pathologists blinded to the PCR results. Relationships between tumour mutation status and prognostic factors were evaluated using a generalised binary logistic regression analysis. RESULTS: ITDs were identified in 13 of 74 cutaneous canine MCT samples, giving an overall prevalence of 17.6% (95% confidence interval: 8.9-26.2%). ITDs were detected in 10 of 18 Patnaik grade III MCTs (55.6%) and 11 of 22 Kiupel high-grade MCTs (50%). Wald chi-square analysis revealed that detection of tumour ITDs was significantly associated with both Patnaik's and Kiupel's histologic grading systems (each: P < 0.001). The presence of the ITDs in MCTs was not associated with signalment, tumour anatomical location or tumour size. CONCLUSION: The prevalence of C-KIT exon 11 ITDs in Australian canine MCTs is similar to the prevalence in overseas canine populations (overall prevalence in Australia approximately 18%). ITDs were more frequently identified in higher grade MCTs.

Evaluation of a capacity building clinical educational model for oral health clinicians treating very young children.

OBJECTIVE: There are significant levels of dental caries in Australian school-aged children, with children aged five years having a mean dmft of 1.3. It has also been identified that, in general, oral health clinicians lack confidence to treat very young children and this study aimed to increase capacity of public sector oral health clinicians to treat preschool children. BASIC RESEARCH DESIGN: An educational program was developed, implemented and evaluated for its capability to increase the confidence and knowledge of oral health clinicians and dental assistants in providing oral care for children aged 12 months to 5 years. RESULTS: In 2011 and 2012, the course was delivered to 36 clinicians (22 dentists, 12 dental therapists, and two oral health therapists) and showed increases in their confidence and knowledge for participants when providing dental procedures to preschool children. CONCLUSIONS: The educational program that was developed and implemented has met its objective of increasing the knowledge and confidence of practicing oral health clinicians and dental assistants in the management of preschool children. Strategies to further enhance the outcomes of this educational program have been proposed.

Short-term effects of military fog oil on the fountain darter (Etheostoma fonticola).

Toxicity tests evaluated chronic and sublethal effects of fog oil (FO) on a freshwater endangered fish. FO is released during military training as an obscurant smoke that can drift into aquatic habitats. Fountain darters, Etheostoma fonticola, of four distinct life stages were exposed under laboratory conditions to three forms of FO. FO was vaporized into smoke and allowed to settle onto water, violently agitated with water, and dosed onto water followed by photo-oxidization by ultraviolet irradiation. Single smoke exposures of spawning adult fish did not affect egg production, egg viability, or adult fish survival in 21-day tests. Multiple daily smoke exposures induced mortality after 5 days for larvae fish. Larvae and juvenile fish were more sensitive than eggs in 96-h lethal concentration (LC50) tests with FO­water mixtures and photo-oxidized FO. Water-soluble FO components photo-modified by ultraviolet radiation were the most toxic, thus indicating the value of examining weathering and aging of chemicals for the best determination of environmental impact.

Potential lost productivity resulting from the global burden of uncorrected refractive error.

OBJECTIVE: To estimate the potential global economic productivity loss associated with the existing burden of visual impairment from uncorrected refractive error (URE). METHODS: Conservative assumptions and national population, epidemiological and economic data were used to estimate the purchasing power parity-adjusted gross domestic product (PPP-adjusted GDP) loss for all individuals with impaired vision and blindness, and for individuals with normal sight who provide them with informal care. FINDINGS: An estimated 158.1 million cases of visual impairment resulted from uncorrected or undercorrected refractive error in 2007; of these, 8.7 million were blind. We estimated the global economic productivity loss in international dollars (I$) associated with this burden at I$ 427.7 billion before, and I$ 268.8 billion after, adjustment for country-specific labour force participation and employment rates. With the same adjustment, but assuming no economic productivity for individuals aged > 50 years, we estimated the potential productivity loss at I$ 121.4 billion. CONCLUSION: Even under the most conservative assumptions, the total estimated productivity loss, in $I, associated with visual impairment from URE is approximately a thousand times greater than the global number of cases. The cost of scaling up existing refractive services to meet this burden is unknown, but if each affected individual were to be provided with appropriate eyeglasses for less than I$ 1000, a net economic gain may be attainable.

Advanced MRI in the management of adult gliomas.

Gliomas are a heterogeneous group that account for approximately 86% of primary brain neoplasms, and include astrocytic and oligodendroglial tumours, as well as a variety of less common histopathological subtypes. Magnetic resonance imaging has become the accepted mode of imaging for the clinical management of these tumours. MRI features bear close resemblance to the histopathology grading and prognosis of these tumours. Currently, conventional MRI is used to aid diagnosis, plan neurosurgical approaches, and monitor response to therapy and disease progression. More recent developments in the field of MRI include MR spectroscopy, perfusion MRI, diffusion-weighted imaging, intraoperative MRI and functional MRI. These newer techniques have been adopted with varying success in the management of adult gliomas. This review focuses on the application of advanced MR imaging in the clinical management of adult gliomas.

Cortical bone viscoelasticity and fixation strength of press-fit femoral stems: an in-vitro model.

Cementless total hip femoral components rely on press-fit for initial stability and bone healing and remodeling for secondary fixation. However, the determinants of satisfactory press-fit are not well understood. In previous studies, human cortical bone loaded circumferentially to simulate press-fit exhibited viscoelastic, or time dependent, behavior. The effect of bone viscoelastic behavior on the initial stability of press-fit stems is not known. Therefore, in the current study, push-out loads of cylindrical stems press-fit into reamed cadaver diaphyseal femoral specimens were measured immediately after assembly and 24 h with stem-bone diametral interference and stem surface treatment as independent variables. It was hypothesized that stem-bone interference would result in a viscoelastic response of bone that would decrease push-out load thereby impairing initial press-fit stability. Results showed that push-out load significantly decreased over a 24 h period due to bone viscoelasticity. It was also found that high and low push-out loads occurred at relatively small amounts of stem-bone interference, but a relationship between stem-bone interference and push-out load could not be determined due to variability among specimens. On the basis of this model, it was concluded that press-fit fixation can occur at relatively low levels of diametral interference and that stem-bone interference elicits viscoelastic response that reduces stem stability over time. From a clinical perspective, these results suggest that there could be large variations in initial press-fit fixation among patients.

MRS of oligodendroglial tumors: correlation with histopathology and genetic subtypes.

BACKGROUND: Oligodendroglial neoplasms with combined loss of chromosomes 1p and 19q may have a good prognosis and respond to procarbazine-lomustine (CCNU)-vincristine (PCV) chemotherapy. OBJECTIVE: To determine whether single voxel magnetic resonance spectroscopy (SV-MRS) obtained through routine clinical practice distinguishes between histopathologic and genetic subtypes of oligodendroglial tumors. METHODS: Forty-eight patients with oligodendroglial tumors (19 oligodendrogliomas and 29 oligoastrocytomas) underwent molecular genetic analysis to determine allelic imbalance in chromosomes 1p36 and 19q13. SV-MRS was obtained pretherapy to determine tumor metabolite ratios. RESULTS: Grade III oligodendroglial tumors had higher choline (Mann-Whitney; p = 0.002), methyl lipid (Mann-Whitney; p = 0.002), and combined methylene lipid and lactate ratios (Mann-Whitney; p < 0.001) than grade II tumors. Lactate did not distinguish between tumor types (Fisher exact test; p = 0.342) or grade (Fisher exact test; p = 0.452). There were no significant associations when tumors were analyzed according to histopathology or genetic subtypes. CONCLUSION: As a noninvasive diagnostic tool used in routine clinical practice, SV-MRS has the potential benefit of determining oligodendroglial tumor grade but not subtypes classified by histopathology or molecular genetics. MRS may be useful for determining the timing of therapy but is unlikely to predict chemosensitivity.

An orientation distribution function for trabecular bone.

We describe a new method for quantifying the orientation of trabecular bone from three-dimensional images. Trabecular lattices from five human vertebrae were decomposed into individual trabecular elements, and the orientation, mass, and thickness of each element were recorded. Continuous functions that described the total mass (M(phi,theta)) and mean thickness (tau(phi,theta)) of all trabeculae as a function of orientation were derived. The results were compared with experimental measurements of the elastic modulus in three principal anatomic directions. A power law scaling relationship between the anisotropies in mass and elastic modulus was observed; the scaling exponent was 1.41 (R2=0.88). As expected, the preponderance of trabecular mass was oriented along the cranial-caudal direction; on average, there was 3.4 times more mass oriented vertically than horizontally. Moreover, the vertical trabeculae were 30% thicker, on average, than the horizontal trabeculae. The vertical trabecular thickness was inversely related to connectivity (R2=0.70; P=0.07), suggesting a possible organization into either few, thick trabeculae or many thin trabeculae. The method, which accounts for the mechanical connectedness of the lattice, provides a rapid way to both visualize and quantify the three-dimensional organization of trabecular bone.