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Employing atomic-scale simulations, the response of a high-angle grain boundary (GB), the soft/hard GB, against external loading was systematically investigated. Under tensile loading close to the hard orientation, strain-induced dynamic recrystallization was observed to initiate through direct soft-to-hard grain reorientation, which was triggered by stress mismatch, inhibited by surface tension from the soft-hard GB, and proceeded by interface ledges. Such grain reorientation corresponds with expansion and contraction of the hard grain along and perpendicular to the loading direction, respectively, accompanied by local atomic shuffling, providing relatively large normal strain of 8.3% with activation energy of 0.04 eV per atom. Tensile strain and residual dislocations on the hard/soft GB facilitate the initiation of dynamic recrystallization by lowering the energy barrier and the critical stress for grain reorientation, respectively.
Chronic low grade inflammation is considered to contribute to the development of experimental diabetic retinopathy (DR). We recently demonstrated that lack of CD40 in mice ameliorates the upregulation of inflammatory molecules in the diabetic retina and prevented capillary degeneration, a hallmark of experimental diabetic retinopathy. Herein, we investigated the contribution of CD40 to diabetes-induced reductions in retinal function via the electroretinogram (ERG) to determine if inflammation plays a role in the development of ERG defects associated with diabetes. We demonstrate that diabetic CD40−/− mice are not protected from reduction to the ERG b-wave despite failing to upregulate inflammatory molecules in the retina. Our data therefore supports the hypothesis that retinal dysfunction found in diabetics occurs independent of the induction of inflammatory processes.
The objective of this study was to evaluate the potential of using Multiplex 3, a hand-held canopy fluorescence sensor, to determine rice nitrogen (N) status at different growth stages. In 2013, a paddy rice field experiment with five N fertilizer treatments and two varieties was conducted in Northeast China. Field samples and fluorescence data were collected simultaneously at the panicle initiation (PI), stem elongation (SE), and heading (HE) stages. Four N status indicators, leaf N concentration (LNC), plant N concentration (PNC), plant N uptake (PNU) and N nutrition index (NNI), were determined. The preliminary results indicated that different N application rates significantly affected most of the fluorescence variables, especially the simple fluorescence ratios (SFR_G, SFR_R), flavonoid (FLAV), and N balance indices (NBI_G, NBI_R). These variables were highly correlated with N status indicators. More studies are needed to further evaluate the accuracy of rice N status diagnosis using fluorescence sensing at different growth stages.
A new cyanolichen, Peltigera islandica sp. nov. in the section Peltigera (‘P. canina group’) is described from Iceland. This species is similar in general appearance to P. rufescens and P. membranacea, but may be recognized by its downturned lobe tips and narrow lobes, respectively. Most thalli are bright emerald green in colour when moist, although a dark khaki green colourmorph is also documented. Monophyly of P. islandica s. lat. (i.e. including P. sp. A sensu O’Brien et al., from Canada) is significantly supported based on ITS sequences and corroborated by molecular synapomorphy (absence of the ITS1 hypervariable region). Analysis of the rbcLX locus indicates the cyanobiont of P. islandica (Nostoc sp.) comprises strains belonging to a pool of Icelandic genotypes, some of which are present in other Peltigera species, including P. “neorufescens”, another taxon new to Iceland collected during this study. Association with photobionts that are shared by other local species suggests P. islandica may be well established in Iceland, but a review of herbarium collections as well as broader field surveys are needed to better characterize its geographical distribution.
This report will try to review briefly the work achieved from 1982 to 1984 in different “subjects to be considered by Commission 31 Time” as adopted in Grenoble 1976. It contains also information provided by Commission members, for which hearty thanks are to be given. The limitation of space required the abbrevation of some institution reports.
Background: Assessment of ischemic penumbra during the acute stage of cerebral infarction is crucial for a decision to initiate thrombolytic therapy and for predicting stroke evolution. Although controversial as a perfect equivalence to penumbra, perfusion weighted imaging (PWI)-diffusion weighted imaging (DWI) mismatch may predict the response to thrombolysis. Due to the reliance on contrast agents in PWI, noninvasive alternatives remain an unmet need. Methods: We herein investigate the potentials of SWI as an alternative to PWI in defining ischemic penumbra and in predicting stroke outcome. A multimodal magnetic resonance imaging work-up which includes conventional magnetic resonance imaging sequences (T1WI, T2WI and FLAIR), DWI, PWI and SWI was performed. The Alberta Stroke Programme Early CT Score (ASPECTS) was used to evaluate the changes in DWI, SWI and PWI. Results: The mismatch of SWI-DWI was comparable with that of PWI-DWI (p>0.05). Furthermore, the grade of prominent vein and the cerebral blood volume in the ipsilateral brain tissue were positively correlated. Conclusions: SWI can be used as a noninvasive alternative to identify occlusive arteries and to evaluate the ischemic penumbra. The susceptibility vein sign may represent thrombosis in arteries whereby being helpful to identify responsible blood vessels in ischemic stroke.
Despite substantial research, uncertainty remains about the clinical and etiological heterogeneity of major depression (MD). Can meaningful and valid subtypes be identified and would they be stable cross-culturally?
Symptoms at their lifetime worst depressive episode were assessed at structured psychiatric interview in 6008 women of Han Chinese descent, age ⩾30 years, with recurrent DSM-IV MD. Latent class analysis (LCA) was performed in Mplus.
Using the nine DSM-IV MD symptomatic A criteria, the 14 disaggregated DSM-IV criteria and all independently assessed depressive symptoms (n = 27), the best LCA model identified respectively three, four and six classes. A severe and non-suicidal class was seen in all solutions, as was a mild/moderate subtype. An atypical class emerged once bidirectional neurovegetative symptoms were included. The non-suicidal class demonstrated low levels of worthlessness/guilt and hopelessness. Patterns of co-morbidity, family history, personality, environmental precipitants, recurrence and body mass index (BMI) differed meaningfully across subtypes, with the atypical class standing out as particularly distinct.
MD is a clinically complex syndrome with several detectable subtypes with distinct clinical and demographic correlates. Three subtypes were most consistently identified in our analyses: severe, atypical and non-suicidal. Severe and atypical MD have been identified in multiple prior studies in samples of European ethnicity. Our non-suicidal subtype, with low levels of guilt and hopelessness, may represent a pathoplastic variant reflecting Chinese cultural influences.
The United States dependence on fossil fuels has become mandatory over the past few decades. The fuel shortage during the 1970s and after Hurricane Katrina has catalyzed a need for creating alternative energy sources, improving the efficacy of these alternative energy sources, and enhancing energy sustainability. The U.S. Department of Energy has set goals to replace 30% of the liquid petroleum transportation fuel with biofuels and to replace 25% of industrial organic chemicals with biomass-derived chemicals by 2025. In the southeast United States, subterranean termites are prevalent and microbes in their gut degrade wood based materials such as cellulose which produce simple sugars that can be used to produce bioethanol. Upon seasonal change, subterranean termites undergo less enzymatic activity and wood-eating capability limiting the amount of sugars that may be produced. This limited activity sparks an interest to investigate this poorly understood phenomenon of how temperature may affect the enzymatic activity in subterranean termites’ guts. In this study, we report the development thermoresponsive biomaterial nanofiber mats containing cellulose to model cellulase activity. Using electrospinning techniques, poly(N-vinylcaprolactam) celluose fiber mats have been prepared via alkaline hydrolysis and labeled with fluorescent tags. Subterranean termites (reticulitermes species) were feed fiber mats for 10 consecutive days to assess enzyme mapping and kinetics. Fluorescent microscopy images confirmed spatial and temporal localization of cellulase enzyme throughout the termite gut upon time and temperature change. These novel high affinity enzyme detection membranes show promise towards future biofuel production.
Compositional patterning in two-phase immiscible alloys during severe plastic deformation at elevated temperatures has been investigated. Kinetic Monte Carlo computer simulations were used to test the proposed idea that patterning derives from a dynamic competition between homogenization by forced chemical mixing and phase separation by thermally activated diffusion [P. Bellon and R.S. Averback, Phys. Rev. Lett.74, 1819 (1995) and F. Wu et al., Acta Mater.54, 2605 (2006)]. We utilize the concept of pair diffusion coefficients to compare thermal diffusion with forced chemical mixing and discuss the fundamentally different behavior with respect to pair separation distance in both mechanisms. While the general ideas of this model are verified and are in good quantitative agreement with our simulations, it is found that the dynamic processes of alloys under high-temperature shear are very complex, even in highly idealized systems, making experimental verification of this model very difficult. We illustrate our findings for a model AB alloy with properties similar to Cu–Ag by showing how alloy morphology and solubility depend on shear rate, temperature, and composition.
The symptoms of major depression (MD) are clinically diverse. Do they form coherent factors that might clarify the underlying nature of this important psychiatric syndrome?
Symptoms at lifetime worst depressive episode were assessed at structured psychiatric interview in 6008 women of Han Chinese descent, age ⩾30 years with recurrent DSM-IV MD. Exploratory factor analysis (EFA) and confirmatoryfactor analysis (CFA) were performed in Mplus in random split-half samples.
The preliminary EFA results were consistently supported by the findings from CFA. Analyses of the nine DSM-IV MD symptomatic A criteria revealed two factors loading on: (i) general depressive symptoms; and (ii) guilt/suicidal ideation. Examining 14 disaggregated DSM-IV criteria revealed three factors reflecting: (i) weight/appetite disturbance; (ii) general depressive symptoms; and (iii) sleep disturbance. Using all symptoms (n = 27), we identified five factors that reflected: (i) weight/appetite symptoms; (ii) general retarded depressive symptoms; (iii) atypical vegetative symptoms; (iv) suicidality/hopelessness; and (v) symptoms of agitation and anxiety.
MD is a clinically complex syndrome with several underlying correlated symptom dimensions. In addition to a general depressive symptom factor, a complete picture must include factors reflecting typical/atypical vegetative symptoms, cognitive symptoms (hopelessness/suicidal ideation), and an agitated symptom factor characterized by anxiety, guilt, helplessness and irritability. Prior cross-cultural studies, factor analyses of MD in Western populations and empirical findings in this sample showing risk factor profiles similar to those seen in Western populations suggest that our results are likely to be broadly representative of the human depressive syndrome.
3D integration enabled by through-silicon-via (TSV) allows continued performance enhancement and power reduction for semiconductor devices, even without further scaling. For TSV wafers with all Applied Materials unit processes, we evaluate the integrity of oxide liner and copper barrier by capacitance-voltage (C-V) and current-voltage (I-V) measurements, from which oxide capacitance, minimum TSV capacitance, and leakage current are extracted. The capacitance values match well with model predictions. The leakage data also demonstrate good wafer-scale uniformity. The liner and barrier quality are further verified with microanalysis techniques.