50 research outputs found

    Polyphosphonate covalent organic frameworks

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    Herein, we report polyphosphonate covalent organic frameworks (COFs) constructed via P-O-P linkages. The materials are synthesized via a single-step condensation reaction of the charge-assisted hydrogen-bonded organic framework, which is constructed from phenylphosphonic acid and 5,10,15,20‐tetrakis[p‐phenylphosphonic acid]porphyrin and is formed by simply heating its hydrogen-bonded precursor without using chemical reagents. Above 210 °C, it becomes an amorphous microporous polymeric structure due to the oligomerization of P-O-P bonds, which could be shown by constant-time solid-state double-quantum 31P nuclear magnetic resonance experiments. The polyphosphonate COF exhibits good water and water vapor stability during the gas sorption measurements, and electrochemical stability in 0.5 M Na2SO4 electrolyte in water. The reported family of COFs fills a significant gap in the literature by providing stable microporous COFs suitable for use in water and electrolytes. Additionally, we provide a sustainable synthesis route for the COF synthesis. The narrow pores of the COF effectively capture CO2

    Development of a High Intensity Neutron Source at the European Spallation Source: The HighNESS project

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    The European Spallation Source (ESS), presently under construction in Lund, Sweden, is a multidisciplinary international laboratory that will operate the world's most powerful pulsed neutron source. Supported by a 3M Euro Research and Innovation Action within the EU Horizon 2020 program, a design study (HighNESS) is now underway to develop a second neutron source below the spallation target. Compared to the first source, located above the spallation target and designed for high cold and thermal brightness, the new source will provide higher intensity, and a shift to longer wavelengths in the spectral regions of cold (2 /- 20 {\AA}), very cold (VCN, 10 /- 120 {\AA}), and ultra cold (UCN, > 500 {\AA}) neutrons. The core of the second source will consist of a large liquid deuterium moderator to deliver a high flux of cold neutrons and to serve secondary VCN and UCN sources, for which different options are under study. The features of these new sources will boost several areas of condensed matter research and will provide unique opportunities in fundamental physics. Part of the HighNESS project is also dedicated to the development of future instruments that will make use of the new source and will complement the initial suite of instruments in construction at ESS. The HighNESS project started in October 2020. In this paper, the ongoing developments and the results obtained in the first year are described.Comment: 10 pages, 10 figures, 14th International Topical Meeting on Nuclear Applications of Accelerators, November 30 to December 4, 2021, Washington, D

    Targeted Inactivation of p12Cdk2ap1, CDK2 Associating Protein 1, Leads to Early Embryonic Lethality

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    Targeted disruption of murine Cdk2ap1, an inhibitor of CDK2 function and hence G1/S transition, results in the embryonic lethality with a high penetration rate. Detailed timed pregnancy analysis of embryos showed that the lethality occurred between embryonic day 3.5 pc and 5.5 pc, a period of implantation and early development of implanted embryos. Two homozygous knockout mice that survived to term showed identical craniofacial defect, including a short snout and a round forehead. Examination of craniofacial morphology by measuring Snout Length (SL) vs. Face Width (FW) showed that the Cdk2ap1+/− mice were born with a reduced SL/FW ratio compared to the Cdk2ap1+/+ and the reduction was more pronounced in Cdk2ap1−/− mice. A transgenic rescue of the lethality was attempted by crossing Cdk2ap1+/− animals with K14-Cdk2ap1 transgenic mice. Resulting Cdk2ap1+/−:K14-Cdk2ap1 transgenic mice showed an improved incidence of full term animals (16.7% from 0.5%) on a Cdk2ap1−/− background. Transgenic expression of Cdk2ap1 in Cdk2ap1−/−:K14-Cdk2ap1 animals restored SL/FW ratio to the level of Cdk2ap1+/−:K14-Cdk2ap1 mice, but not to that of the Cdk2ap1+/+:K14-Cdk2ap1 mice. Teratoma formation analysis using mESCs showed an abrogated in vivo pluripotency of Cdk2ap1−/− mESCs towards a restricted mesoderm lineage specification. This study demonstrates that Cdk2ap1 plays an essential role in the early stage of embryogenesis and has a potential role during craniofacial morphogenesis

    3640 Unique EST Clusters from the Medaka Testis and Their Potential Use for Identifying Conserved Testicular Gene Expression in Fish and Mammals

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    BACKGROUND: The fish medaka is the first vertebrate capable of full spermatogenesis in vitro from self-renewing spermatogonial stem cells to motile test-tube sperm. Precise staging and molecular dissection of this process has been hampered by the lack of suitable molecular markers. METHODOLOGY AND PRINCIPAL FINDINGS: We have generated a normalized medaka testis cDNA library and obtained 7040 high quality sequences representing 3641 unique gene clusters. Among these, 1197 unique clusters are homologous to known genes, and 2444 appear to be novel genes. Ontology analysis shows that the 1197 gene products are implicated in diverse molecular and cellular processes. These genes include markers for all major types of testicular somatic and germ cells. Furthermore, markers were identified for major spermatogenic stages ranging from spermatogonial stem cell self-renewal to meiosis entry, progression and completion. Intriguingly, the medaka testis expresses at least 13 homologs of the 33 mouse X-chromosomal genes that are enriched in the testis. More importantly, we show that key components of several signaling pathways known to be important for testicular function in mammals are well represented in the medaka testicular EST collection. CONCLUSIONS/SIGNIFICANCE: Medaka exhibits a considerable similarity in testicular gene expression to mammals. The medaka testicular EST collection we obtained has wide range coverage and will not only consolidate our knowledge on the comparative analysis of known genes' functions in the testis but also provide a rich resource to dissect molecular events and mechanism of spermatogenesis in vivo and in vitro in medaka as an excellent vertebrate model

    Polyphosphonate covalent organic frameworks

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    Herein, we report polyphosphonate covalent organic frameworks COFs constructed via P O P linkages. The materials are synthesized via a single step condensation reaction of the charge assisted hydrogen bonded organic framework, which is constructed from phenylphosphonic acid and 5,10,15,20 amp; 8208;tetrakis[p amp; 8208;phenylphosphonic acid]porphyrin and is formed by simply heating its hydrogen bonded precursor without using chemical reagents. Above 210 amp; 8201; C, it becomes an amorphous microporous polymeric structure due to the oligomerization of P O P bonds, which could be shown by constant time solid state double quantum 31P nuclear magnetic resonance experiments. The polyphosphonate COF exhibits good water and water vapor stability during the gas sorption measurements, and electrochemical stability in 0.5 amp; 8201;M Na2SO4 electrolyte in water. The reported family of COFs fills a significant gap in the literature by providing stable microporous COFs suitable for use in water and electrolytes. Additionally, we provide a sustainable synthesis route for the COF synthesis. The narrow pores of the COF effectively capture CO

    RNA motif search with data-driven element ordering

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    BACKGROUND: In this paper, we study the problem of RNA motif search in long genomic sequences. This approach uses a combination of sequence and structure constraints to uncover new distant homologs of known functional RNAs. The problem is NP-hard and is traditionally solved by backtracking algorithms. RESULTS: We have designed a new algorithm for RNA motif search and implemented a new motif search tool RNArobo. The tool enhances the RNAbob descriptor language, allowing insertions in helices, which enables better characterization of ribozymes and aptamers. A typical RNA motif consists of multiple elements and the running time of the algorithm is highly dependent on their ordering. By approaching the element ordering problem in a principled way, we demonstrate more than 100-fold speedup of the search for complex motifs compared to previously published tools. CONCLUSIONS: We have developed a new method for RNA motif search that allows for a significant speedup of the search of complex motifs that include pseudoknots. Such speed improvements are crucial at a time when the rate of DNA sequencing outpaces growth in computing. RNArobo is available at http://compbio.fmph.uniba.sk/rnarobo. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12859-016-1074-x) contains supplementary material, which is available to authorized users

    Hormone therapy: the European women's perspective

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    Sensorless control for buried magnet PMSM based on direct flux control and fuzzy logic

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    Direct flux control (DFC) is one of the sensorless methods, which is used to acquire the electrical rotor position of permanent magnet synchronous machines (PMSMs) for all speeds. The DFC is implemented on a TriCore PXROS platform, which is connected to the real PMSM. Flux linkage signals are measured to calculate the electrical rotor position by using an approximation function. Due to the weak intensity of the measured flux linkage signals of the buried magnet PMSM, a fuzzy logic is selected as a tool to overcome the mentioned problem. The fuzzy logic is designed based on the flux intensity characteristics, which are recognized by driving the motors. Thus, a flux intensity management (FIM) strategy by fuzzy logic is proposed in this paper to solve the obstacle. Consequently, the buried magnet PMSM electrical rotor positions can be acquired for all speeds by employing the DFC and the FIM methods
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