Electrification of the chemical industry Barton, John L.
Science (American Association for the Advancement of Science),
06/2020, Letnik:
368, Številka:
6496
Journal Article
Recenzirano
Performing chemical synthesis with renewable electricity can reduce carbon emissions
Curbing carbon emissions while maintaining quality of life is a global challenge for manufacturing processes that ...will require process innovation. One approach is replacing energy from the burning of carbon-based fuels with energy supplied by “green” electrons. This goal can be achieved in some cases by simply replacing heat supplied by combustion with electrical heating (
1
). In chemical synthesis, it can also more elegantly supply reaction energy through electrochemistry. On page 1228 of this issue, Leow
et al.
(
2
) propose an electrochemical route to ethylene oxide (EO) and propylene oxide (PO) that promises cleaner, more efficient, and more selective processing. Ethylene and propylene were epoxidized electrochemically to EO and PO, respectively, at industrially relevant current densities with Faradaic (electron-specific) selectivities ∼70% to the target epoxide (
2
).
The amount and spectral content of the light reflected by most natural surfaces depends on the structure of the light field, the observer’s viewing position, and 3D surface geometry, particularly for ...specular (glossy) surfaces. A growing body of data has demonstrated that perceived surface gloss can vary as a function of its 3D shape 1–5 and its illumination field 6–12, but there is currently no explanation for these effects. Here, we show that the perception of gloss can be understood as a direct consequence of image properties that covary with surface geometry and the illumination field. We show that different illumination fields can generate qualitatively different patterns of interaction between perceived gloss and 3D surface geometry. Despite the complexity and variability of these interactions, we demonstrate that the perception (and misperception) of gloss is well predicted by the way that each illumination field modulates the size, contrast, sharpness, and depth of specular reflections. Our results provide a coherent explanation of the effects of extrinsic scene variables on perceived gloss 1–13, and our methods suggest a general technique for assessing the role of specific image properties in modulating our visual experience of material properties.
Display omitted
► Investigated why irrelevant scene attributes influence perception of surface gloss ► Found gloss judgments exhibit complex interactions between illumination and 3D shape ► Four proximal cues can account for interactions between light field, shape, and gloss ► Suggests that these cues mediate the perception and misperception of gloss
The visual system relies on patterns of light to provide information about the layout of objects that populate our environment. Light is structured by the way it interacts with the three-dimensional ...shape, reflectance, and transmittance properties of objects. The input for vision is therefore a complex, conflated mixture of different sources of physical variation that the brain must somehow disentangle to recover the intrinsic properties of the objects and materials that fill the world.
We introduce an Active Vertex Model (AVM) for cell-resolution studies of the mechanics of confluent epithelial tissues consisting of tens of thousands of cells, with a level of detail inaccessible to ...similar methods. The AVM combines the Vertex Model for confluent epithelial tissues with active matter dynamics. This introduces a natural description of the cell motion and accounts for motion patterns observed on multiple scales. Furthermore, cell contacts are generated dynamically from positions of cell centres. This not only enables efficient numerical implementation, but provides a natural description of the T1 transition events responsible for local tissue rearrangements. The AVM also includes cell alignment, cell-specific mechanical properties, cell growth, division and apoptosis. In addition, the AVM introduces a flexible, dynamically changing boundary of the epithelial sheet allowing for studies of phenomena such as the fingering instability or wound healing. We illustrate these capabilities with a number of case studies.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In this primer, Anderson provides an overview of some central topics in mid-level vision, highlighting some recent advances in our understanding of how the human visual system identifies different ...environmental sources of optical structure.
BACKGROUND:The number of total shoulder arthroplasties performed in the United States increased slightly between 1990 and 2000. However, the incidence of shoulder arthroplasty in recent years has not ...been well described. The purpose of the present study was to examine recent trends in shoulder hemiarthroplasty and total shoulder arthroplasty along with the common reasons for these surgical procedures in the United States.
METHODS:We modeled the incidence of shoulder arthroplasty from 1993 to 2008 with use of the Nationwide Inpatient Sample. On the basis of hemiarthroplasty and total shoulder arthroplasty cases that were identified with use of surgical procedure codes, we conducted a design-based analysis to calculate national estimates.
RESULTS:While the annual number of hemiarthroplasties grew steadily, the number of total shoulder arthroplasties showed a discontinuous jump (p < 0.01) in 2004 and increased with a steeper linear slope (p < 0.01) since then. As a result, more total shoulder arthroplasties than hemiarthroplasties have been performed annually since 2006. Approximately 27,000 total shoulder arthroplasties and 20,000 hemiarthroplasties were performed in 2008. More than two-thirds of total shoulder arthroplasties were performed in adults with an age of sixty-five years or more. Osteoarthritis was the primary diagnosis for 43% of hemiarthroplasties and 77% of total shoulder arthroplasties in 2008, with fracture of the humerus as the next most common primary diagnosis leading to hemiarthroplasty.
CONCLUSIONS:The number of shoulder arthroplasties, particularly total shoulder arthroplasties, is growing faster than ever. The use of reverse total arthroplasty, which was approved by the United States Food and Drug Administration in November 2003, may be part of the reason for the greater increase in the number of total shoulder arthroplasties. A long-term follow-up study is warranted to evaluate total shoulder arthroplasty in terms of patient outcomes, safety, and implant longevity.
To update recommendations of the ASCO systemic therapy for hormone receptor (HR)-positive metastatic breast cancer (MBC) guideline.
An Expert Panel conducted a systematic review to identify new, ...potentially practice-changing data.
Fifty-one articles met eligibility criteria and form the evidentiary basis for the recommendations.
Alpelisib in combination with endocrine therapy (ET) should be offered to postmenopausal patients, and to male patients, with HR-positive, human epidermal growth factor receptor 2 (HER2)-negative,
-mutated, ABC, or MBC following prior endocrine therapy with or without a cyclin-dependent kinase (CDK) 4/6 inhibitor. Clinicians should use next-generation sequencing in tumor tissue or cell-free DNA in plasma to detect
mutations. If no mutation is found in cell-free DNA, testing in tumor tissue, if available, should be used as this will detect a small number of additional patients with
mutations. There are insufficient data at present to recommend routine testing for
mutations to guide therapy for HR-positive, HER2-negative MBC. For
or
mutation carriers with metastatic HER2-negative breast cancer, olaparib or talazoparib should be offered in the 1st-line through 3rd-line setting. A nonsteroidal aromatase inhibitor (AI) and a CDK4/6 inhibitor should be offered to postmenopausal women with treatment-naïve HR-positive MBC. Fulvestrant and a CDK4/6 inhibitor should be offered to patients with progressive disease during treatment with AIs (or who develop a recurrence within 1 year of adjuvant AI therapy) with or without one line of prior chemotherapy for metastatic disease, or as first-line therapy. Treatment should be limited to those without prior exposure to CDK4/6 inhibitors in the metastatic setting.Additional information can be found at www.asco.org/breast-cancer-guidelines.
Diffuse intrinsic pontine glioma (DIPG), or high-grade brainstem glioma (BSG), is one of the major causes of brain tumor-related deaths in children. Its prognosis has remained poor despite numerous ...efforts to improve survival. Panobinostat, a histone deacetylase inhibitor, is a targeted agent that has recently shown pre-clinical efficacy and entered a phase I clinical trial for the treatment of children with recurrent or progressive DIPG.
A collaborative pre-clinical study was conducted using both a genetic BSG mouse model driven by PDGF-B signaling, p53 loss, and ectopic H3.3-K27M or H3.3-WT expression and an H3.3-K27M orthotopic DIPG xenograft model to confirm and extend previously published findings regarding the efficacy of panobinostat in vitro and in vivo.
In vitro, panobinostat potently inhibited cell proliferation, viability, and clonogenicity and induced apoptosis of human and murine DIPG cells. In vivo analyses of tissue after short-term systemic administration of panobinostat to genetically engineered tumor-bearing mice indicated that the drug reached brainstem tumor tissue to a greater extent than normal brain tissue, reduced proliferation of tumor cells and increased levels of H3 acetylation, demonstrating target inhibition. Extended consecutive daily treatment of both genetic and orthotopic xenograft models with 10 or 20 mg/kg panobinostat consistently led to significant toxicity. Reduced, well-tolerated doses of panobinostat, however, did not prolong overall survival compared to vehicle-treated mice.
Our collaborative pre-clinical study confirms that panobinostat is an effective targeted agent against DIPG human and murine tumor cells in vitro and in short-term in vivo efficacy studies in mice but does not significantly impact survival of mice bearing H3.3-K27M-mutant tumors. We suggest this may be due to toxicity associated with systemic administration of panobinostat that necessitated dose de-escalation.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The purpose of the study was to examine use of the Modified Checklist for Autism in Toddlers (M-CHAT) as an autism-specific screening instrument in a large, geographically diverse pediatrics-based ...sample.
The M-CHAT and the M-CHAT Follow-Up (M-CHAT/F) were used to screen 18,989 toddlers at pediatric well-child visits in 2 US geographic regions. Pediatricians directly referred children to ascertain potential missed screening cases. Screen-positive children received the M-CHAT/F; children who continued to screen positive after the M-CHAT/F received a diagnostic evaluation.
Results indicated that 54% of children who screened positive on the M-CHAT and M-CHAT/F presented with an autism spectrum disorder (ASD), and 98% presented with clinically significant developmental concerns warranting intervention. An M-CHAT total score cutoff of ≥3 identifies nearly all screen-positive cases, and for ease of scoring the use of only the M-CHAT total score cutoff is recommended. An M-CHAT total score of 7 serves as an appropriate clinical cutoff, and providers can bypass the M-CHAT/F and refer immediately to evaluation and intervention if a child obtains a score of ≥7.
This study provides empirical support for the utility of population screening for ASD with the use of the M-CHAT in a primary care setting. Results suggest that the M-CHAT continues to be an effective screening instrument for ASD when the 2-step screening process is used. The M-CHAT is widely used at pediatric offices, and this study provides updated results to facilitate use and scoring of the M-CHAT by clinical providers.
The problem of extracting the three-dimensional (3D) shape and material properties of surfaces from images is considered to be inherently ill posed. It is thought that a priori knowledge about either ...3D shape is needed to infer material properties, or knowledge about material properties are needed to derive 3D shape. Here, we show that there is information in images that cospecify both the material composition and 3D shape of light permeable (translucent) materials. Specifically, we show that the intensity gradients generated by subsurface scattering, the shape of self-occluding contours, and the distribution of specular reflections covary in systematic ways that are diagnostic of both the surface's 3D shape and its material properties. These sources of image covariation emerge from being causally linked to a common environmental source: 3D surface curvature. We show that these sources of covariation take the form of "photogeometric constraints," which link variations in intensity (photometric constraints) to the sign and direction of 3D surface curvature (geometric constraints). We experimentally demonstrate that this covariation generates emergent cues that the visual system exploits to derive the 3D shape and material properties of translucent surfaces and demonstrate the potency of these cues by constructing counterfeit images that evoke vivid percepts of 3D shape and translucency. The concepts of covariation and cospecification articulated herein suggest a principled conceptual path forward for identifying emergent cues that can be used to solve problems in vision that have historically been assumed to be ill posed.
PDF
