scholarly journals Rational synthesis of interpenetrated 3D covalent organic frameworks for asymmetric photocatalysis

2020 ◽  
Vol 11 (6) ◽  
pp. 1494-1502 ◽  
Author(s):  
Xing Kang ◽  
Xiaowei Wu ◽  
Xing Han ◽  
Chen Yuan ◽  
Yan Liu ◽  
...  
Keyword(s):  
Sustainable Production ◽  
Great Promise ◽  
Fine Chemicals ◽  
Covalent Organic Frameworks

Covalent organic frameworks (COFs) show great promise as heterogeneous photocatalysts, but they have not yet been explored for asymmetric photocatalysis, which is important for the sustainable production of pharmaceuticals and fine chemicals.

scholarly journals Consolidated production of coniferol and other high-value aromatic alcohols directly from lignocellulosic biomass

2020 ◽  
Vol 22 (1) ◽  
pp. 144-152 ◽  
Author(s):  
Robson Tramontina ◽  
James L. Galman ◽  
Fabio Parmeggiani ◽  
Sasha R. Derrington ◽  
Timothy D. H. Bugg ◽  
...  
Keyword(s):  
Lignocellulosic Biomass ◽  
Sustainable Production ◽  
Fine Chemicals ◽  
Oil Reserves ◽  
Renewable Biomass ◽  
Aromatic Alcohols ◽  
Potential Alternative ◽  
Continued Use

Sustainable production of fine chemicals and biofuels from renewable biomass offers a potential alternative to the continued use of finite geological oil reserves.

scholarly journals Ultra-fast single-crystal polymerization of large-sized covalent organic frameworks

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Lan Peng ◽  
Qianying Guo ◽  
Chaoyu Song ◽  
Samrat Ghosh ◽  
Huoshu Xu ◽  
...  
Keyword(s):  
Single Crystal ◽  
Single Crystals ◽  
Growth Time ◽  
Great Promise ◽  
Covalent Organic Frameworks ◽  
Environmental Friendliness ◽  
Traditional Concept ◽  
Crystalline Materials ◽  
Practical Applications ◽  
Low Efficiency

AbstractIn principle, polymerization tends to produce amorphous or poorly crystalline materials. Efficiently producing high-quality single crystals by polymerization in solvent remains as an unsolved issue in chemistry, especially for covalent organic frameworks (COFs) with highly complex structures. To produce μm-sized single crystals, the growth time is prolonged to >15 days, far away from the requirements in practical applications. Here, we find supercritical CO2 (sc-CO2) accelerates single-crystal polymerization by 10,000,000 folds, and produces two-dimensional (2D) COF single crystals with size up to 0.2 mm within 2~5 min. Although it is the fastest single-crystal polymerization, the growth in sc-CO2 leads to not only the largest crystal size of 2D COFs, but also higher quality with improved photoconductivity performance. This work overcomes traditional concept on low efficiency of single-crystal polymerization, and holds great promise for future applications owing to its efficiency, industrial compatibility, environmental friendliness and universality for different crystalline structures and linkage bonds.

Are HOLZ lines kinematic in off-zone-axis orientation?

1993 ◽  
Vol 51 ◽  
pp. 692-693
Author(s):  
J. M. Zuo ◽  
A. L. Weickenmeier ◽  
R. Holmestad ◽  
J. C. H. Spence
Keyword(s):  
Structure Determination ◽  
Standard Procedure ◽  
High Order ◽  
Zone Axis ◽  
Great Promise ◽  
Line Position ◽  
Measured Intensity ◽  
Constant Intensity ◽  
Axis Orientation ◽  
Diffraction Condition

The application of high order reflections in a weak diffraction condition off the zone axis center, including those in high order laue zones (HOLZ), holds great promise for structure determination using convergent beam electron diffraction (CBED). It is believed that in this case the intensities of high order reflections are kinematic or two-beam like. Hence, the measured intensity can be related to the structure factor amplitude. Then the standard procedure of structure determination in crystallography may be used for solving unknown structures. The dynamic effect on HOLZ line position and intensity in a strongly diffracting zone axis is well known. In a weak diffraction condition, the HOLZ line position may be approximated by the kinematic position, however, it is not clear whether this is also true for HOLZ intensities. The HOLZ lines, as they appear in CBED patterns, do show strong intensity variations along the line especially near the crossing of two lines, rather than constant intensity along the Bragg condition as predicted by kinematic or two beam theory.

Development of the UHV-STM

1990 ◽  
Vol 48 (1) ◽  
pp. 322-323
Author(s):  
M. Iwatsuki ◽  
S. Kitamura ◽  
A. Mogami
Keyword(s):  
Surface Science ◽  
Real Space ◽  
Atomic Scale ◽  
Scanning Tunneling ◽  
Great Promise ◽  
Force Microscopy ◽  
Atomic Force ◽  
Stm Image ◽  
Surface Construction ◽  
Very High

Since Binnig, Rohrer and associates observed real-space topographic images of Si(111)-7×7 and invented the scanning tunneling microscope (STM),1) the STM has been accepted as a powerful surface science instrument.Recently, many application areas for the STM have been opened up, such as atomic force microscopy (AFM), magnetic force microscopy (MFM) and others. So, the STM technology holds a great promise for the future.The great advantages of the STM are its high spatial resolution in the lateral and vertical directions on the atomic scale. However, the STM has difficulty in identifying atomic images in a desired area because it uses piezoelectric (PZT) elements as a scanner.On the other hand, the demand to observe specimens under UHV condition has grown, along with the advent of the STM technology. The requirment of UHV-STM is especially very high in to study of surface construction of semiconductors and superconducting materials on the atomic scale. In order to improve the STM image quality by keeping the specimen and tip surfaces clean, we have built a new UHV-STM (JSTM-4000XV) system which is provided with other surface analysis capability.

Covalent organic frameworks: an ideal platform for designing ordered materials and advanced applications

2021 ◽  
Author(s):  
Ruoyang Liu ◽  
Ke Tian Tan ◽  
Yifan Gong ◽  
Yongzhi Chen ◽  
Zhuoer Li ◽  
...  
Keyword(s):  
Covalent Organic Frameworks ◽  
2D And 3D ◽  
Advanced Applications

Covalent organic frameworks offer a molecular platform for integrating organic units into periodically ordered yet extended 2D and 3D polymers to create topologically well-defined polygonal lattices and built-in discrete micropores and/or mesopores.

Behavioral Genetics: Concepts for Research and Practice in Language Development and Disorders

1995 ◽  
Vol 38 (5) ◽  
pp. 1126-1142 ◽  
Author(s):  
Jeffrey W. Gilger
Keyword(s):  
Language Development ◽  
Behavioral Genetics ◽  
State Of The Art ◽  
Genetic Research ◽  
Great Promise ◽  
Behavioral Genetic ◽  
Fine Grained ◽  
Future Goals ◽  
Current State ◽  
Research Designs

This paper is an introduction to behavioral genetics for researchers and practioners in language development and disorders. The specific aims are to illustrate some essential concepts and to show how behavioral genetic research can be applied to the language sciences. Past genetic research on language-related traits has tended to focus on simple etiology (i.e., the heritability or familiality of language skills). The current state of the art, however, suggests that great promise lies in addressing more complex questions through behavioral genetic paradigms. In terms of future goals it is suggested that: (a) more behavioral genetic work of all types should be done—including replications and expansions of preliminary studies already in print; (b) work should focus on fine-grained, theory-based phenotypes with research designs that can address complex questions in language development; and (c) work in this area should utilize a variety of samples and methods (e.g., twin and family samples, heritability and segregation analyses, linkage and association tests, etc.).

Antithrombotic Therapy for DVT/PE

1997 ◽  
Vol 17 (03) ◽  
pp. 161-162
Author(s):  
Thomas Hyers
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight Heparin ◽  
Oral Anticoagulants ◽  
Cost Effective ◽  
Therapeutic Agents ◽  
Great Promise ◽  
Term Therapy ◽  
Low Molecular Weight ◽  
Long Term Therapy

SummaryProblems with unfractionated heparin as an antithrombotic have led to the development of new therapeutic agents. Of these, low molecular weight heparin shows great promise and has led to out-patient therapy of DVT/PE in selected patients. Oral anticoagulants remain the choice for long-term therapy. More cost-effective ways to give oral anticoagulants are needed.

Antiplatelet Therapy in Acute Coronary Syndromes

2010 ◽  
Vol 6 (1) ◽  
pp. 58
Author(s):  
Sasha Koul ◽  
David Erlinge ◽  
◽  
Keyword(s):  
Platelet Function ◽  
Acute Coronary Syndromes ◽  
New Drugs ◽  
Antiplatelet Drugs ◽  
Bleeding Complications ◽  
Great Promise ◽  
Mortality Data ◽  
Poor Responders ◽  
Coronary Syndromes

Drugs inhibiting platelet function play a major role in the treatment of acute coronary syndromes (ACS). The first drug used, which is still considered the cornerstone of therapy today, is aspirin. Although very impressive in acutely decreasing rates of myocardial infarction as well as death, long-term data are scarce, despite our current recommendation for lifelong aspirin. The thienopyridines, most notably clopidogrel, are the next line of antiplatelet drugs. Well-documented data support the usage of clopidogrel for non-STEMI-ACS (NSTE-ACS). Although positive mortality data exist regarding clopidogrel and STEMI patients in a medically treated population, including thrombolysis, no larger amounts of randomised data exist in a primary PCI setting. Poor responders to aspirin and/or clopidogrel are a clinical problem, with these individuals constituting a higherrisk group for recurrent ischaemic events. Whereas very little can be done regarding aspirin resistance, clopidogrel resistance might be diminished by increasing the dosage or changing to more potent and newer-generation antiplatelet drugs. The role of glycoprotein IIb/IIIa inhibitors has diminished drastically and instead paved the way for thrombin antagonists (bivalirudin), which have fewer bleeding complications with resulting better long-term mortality. Novel adenosine diphosphate (ADP)-receptor blockers such as prasugrel and ticagrelor have shown increased efficacy over clopidogrel and hold great promise for the future. However, not all patients may benefit from these new drugs and economic constraints may also limit their use. Platelet function tests could possibly help in identifying risk groups in need of stronger platelet inhibition.

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