Stabilization Technology and Tool Change Technology for Open Face with Pressure Open

2021 ◽  
pp. 197-266
Author(s):  
Jian Chen ◽  
Fanlu Min
Keyword(s):  
Open Face

Photochemical and Electrochemical Reduction of Carbon Dioxide Catalyzed by a Polyoxometalate-Organic Photosensitizer Complex

2018 ◽  
Author(s):  
Chandan Dey ◽  
Ronny Neumann
Keyword(s):  
Carbon Dioxide ◽  
Cyclic Voltammetry ◽  
Formic Acid ◽  
Electrochemical Reduction ◽  
Mass Spectroscopy ◽  
Photochemical Reactions ◽  
Reducing Agent ◽  
Covalent Attachment ◽  
Hybrid Complex ◽  
Open Face

<p>A manganese substituted Anderson type polyoxometalate, [MnMo<sub>6</sub>O<sub>24</sub>]<sup>9-</sup>, tethered with an anthracene photosensitizer was prepared and used as catalyst for CO<sub>2</sub> reduction. The polyoxometalate-photosensitizer hybrid complex, obtained by covalent attachment of the sensitizer to only one face of the planar polyoxometalate, was characterized by NMR, IR and mass spectroscopy. Cyclic voltammetry measurements show a catalytic response for the reduction of carbon dioxide, thereby suggesting catalysis at the manganese site on the open face of the polyoxometalate. Controlled potentiometric electrolysis showed the reduction of CO<sub>2</sub> to CO with a TOF of ~15 sec<sup>-1</sup>. Further photochemical reactions showed that the polyoxometalate-anthracene hybrid complex was active for the reduction of CO<sub>2</sub> to yield formic acid and/or CO in varying amounts dependent on the reducing agent used. Control experiments showed that the attachment of the photosensitizer to [MnMo<sub>6</sub>O<sub>24</sub>]<sup>9-</sup> is necessary for photocatalysis.</p><div><br></div>

Macropolyhedral Boron-Containing Cluster Chemistry. A Metallathiaborane from S2B17H17: Isolation and Characterisation of [(PMe2Ph)2PtS2B16H16]; A neo-arachno Ten-Vertex Cluster Shape, and the Constitution of the [arachno-B10H15]- Anion

2005 ◽  
Vol 70 (4) ◽  
pp. 430-440 ◽  
Author(s):  
Michael J. Carr ◽  
Michael G. S. Londesborough ◽  
Jonathan Bould ◽  
Ivana Císařová ◽  
Bohumil Štíbr ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Sodium Hydride ◽  
Hydrogen Atoms ◽  
Subsequent Reaction ◽  
Cluster Chemistry ◽  
Cluster Shape ◽  
Open Face

The deprotonation of S2B17H17 with sodium hydride and subsequent reaction with [PtCl2(PMe2Ph)2] gives the new macropolyhedral metallathiaborane [(PMe2Ph)2PtS2B16H16], of which the cluster consists of a conventional eleven-vertex nido {SB10} unit, fused, with two boron atoms in common, with a {PtSB8} unit of unique ten-vertex neo-arachno constitution and geometry. The latter geometry suggests a configuration for the previously structurally uncharacterised [B10H15]- anion; starting from this configuration, DFT calculations of structure and thence of boron nuclear shieldings, which are found very closely to mimic those found experimentally, thence support a fluxional structure for [B10H15]- with three {BHB(bridging)} and two {BH(endo)} hydrogen atoms around a six-membered open face.

scholarly journals Quantifying false positional corrections due to facial motion using SGRT with open‐face Masks

2021 ◽  
Author(s):  
Victoria Bry ◽  
Anna Laura Licon ◽  
James McCulloch ◽  
Neil Kirby ◽  
Pamela Myers ◽  
...  
Keyword(s):  
Facial Motion ◽  
Open Face

scholarly journals ANALYSIS OF DEVELOPMENT NEEDS VIRTUAL LABORATORY FOR LEARNING VOCATIONAL SCHOOL PRACTICES IN THE PANDEMIC TIME COVID-19

2021 ◽  
Vol 5 (2) ◽  
Author(s):  
Eskawati Musyarofah Bunyamin ◽  
Eveline Siregar Siregar ◽  
Dwi Kusumawardani Kusumawardani
Keyword(s):  
Health And Safety ◽  
Vocational School ◽  
Virtual Laboratory ◽  
Ministry Of Education ◽  
School Practices ◽  
Face To Face ◽  
Need Analysis ◽  
Virtual Laboratories ◽  
Face To Face Learning ◽  
Open Face

During the COVID-19 pandemic, schools did not open face-to-face learning services. The Ministry of Education and Culture has issued a policy learning from Home (BDR) to support the principles of the Education Policy in the COVID-19 Pandemic that the health and safety of students, educators, education personnel, families, and the community is the top priority. However, learning in Vocational School (SMK) is mostly based on practice so that BDR activities cannot be implemented. One thing that is done to overcome this is that some practicum activities can be executed using multimedia known as virtual laboratories. The aim of this study is to conduct a need analysis for the development of a virtual laboratory.  Needs analysis is carried out to gather data about gaps and needs as well profiles of students that can be used as a basis or reference in developing virtual laboratory at the next stage. Data collection was carried out by means of observation, interviews, and distributing questionnaires. The results showed that a virtual laboratory was needed to support practical learning for vocational students.

scholarly journals Pengaruh penggunaan helm terhadap cedera kraniofasial berdasarkan skor FISS dan CT Marshall

2017 ◽  
Vol 9 (2) ◽  
Author(s):  
Hendrik Mengga ◽  
Mendy Hatibie ◽  
Eko Prasetyo ◽  
Maximillian Ch. Oley
Keyword(s):  
Scoring System ◽  
Head Injuries ◽  
Maxillofacial Injury ◽  
Intracranial Injury ◽  
Cross Sectional ◽  
Craniofacial Trauma ◽  
Maxillofacial Abnormalities ◽  
Cross Sectional Design ◽  
Full Face ◽  
Open Face

Abstract: Helmet can reduce head trauma as well as maxillofacial trauma due to motorcycle accident. This study was aimed to prove the effect of helmet and its type in reducing craniofacial injury. Any intracranial abnormalities were evaluated with the CT Marshall scoring system and maxillofacial abnormalities were evaluated with FISS. This was an analytical comparative study with a cross sectional design. The results showed that there were 72 patients with craniofacial trauma; 59 patients with intracranial abnormalities and 24 patients with maxillofacial abnormalities. There were 43.1% patients that wore helmet; 31.9% of them wore open-face helmet. Data were analyzed by using the unpaired t-tests. Based on FISS, the effect of helmet on maxillofacial injury obtained a t-value of 0.787 (P = 0.217) which indicated that there was no difference in FISS scores between patients wearing helmet and not. Based on the CT Marshall scoring system, the effect of helmet on the intracranial injury obtained a t-value of 1.822 (P = 0.036) which indicated that there was a difference in scores between patients wearing helmet and not. This meant that wearing helmets had some influence on the occurence of head injuries. Based on FISS, the impacts of full-face helmet and open-face helmet on maxillofacial injuries obtained a t-value of 1.890 (P = 0.034) which indicated that there was a difference in FISS between the two types of helmets. Based on the CT Marshall scoring system, the impacts of full-face helmet and open-face helmet on intracranial injuries obtained a t-value of 1.714 (P = 0.049) which indicated that there was a difference in CT Marshall scores between the two types of helmets. Conclusion: Helmet and its type, full-face and open-face, had some influence on the occurence of either maxillofacial or intracranial injuries.Keywords: craniofacial injury, motorcycle, helmetAbstrak: Penggunaan helm dapat mengurangi kejadian trauma kepala dan trauma maksiofasial akibat kecelakaan sepeda motor. Penelitian ini bertujuan untuk membuktikan bahwa pemakaian helm dan tipe helm berperan dalam menurunkan cedera kraniofasial. Abnormalitas intrakranial dievaluasi dengan skoring CT Marshall dan abnormalitas maksilofasial dievaluasi dengan FISS. Jenis penelitian ialah analitik komparatif dengan desain potong lintang. Hasil penelitian mendapatkan 72 pasien dengan trauma kraniofasial; 59 pasien dengan abnormalitas intrakranial dan 24 pasien dengan abnormalitas maksilofasial. Terdapat 43,1% pasien yang menggunakan helm; 31,9% menggunakan helm open-face. Data dianalisis menggyunakan uji t tidak berpasangan. Berdasarkan FISS, efek helm terhadap cedera maksilofasial mendapatkan t = 0,787 (P = 0,217) yag menunjukkan tidak terdapat perbedaan skor antara pasien yang menggunakan dan tidak menggunakan helm. Berdasarkan skoring CT Marshall, efek helm terhadap cedera intrakranial mendapatkan t = 1,822 (P = 0,036) yang menunjukkan terdapat perbedaan skor antara pasien yang menggunakan dan tidak menggunakan helm. Hal ini memperlihatkan bahwa penggunaan helm berpengaruh terhadap kejadian cedera kepala. Berdasarkan FISS, dampak jenis helm full-face dan open-face terhadap cedera maksilofasial mendapatkan t = 1,890 (P = 0,034) yang menyatakan terdapat perbedaan skor FISS antara pengggunaan kedua jenis helm. Berdasarkan skoring CT Marshall, dampak helm full-face dan open-face terhadap cedera intrakranial mendapatkan t = 1,714 (P = 0,049) yang menunjukkan terdapat perbedaan skor CT Marshall antara penggunaan kedua jenis helm. Simpulan: Penggunaan helm dan jenis helm (full-face dan open-face) memengaruhi terjadinya cedera maksilofasial dan intrakranial.Kata kunci: cedera kraniofasial, sepeda motor, helm

The Burke Synthesis of ( + )-Didemniserinolipid B

2011 ◽  
Author(s):  
Douglass Taber
Keyword(s):  
First Generation ◽  
Secondary Alcohol ◽  
Unsaturated Ester ◽  
Unsaturated Ketone ◽  
Grubbs Catalyst ◽  
University Of Wisconsin ◽  
Set Up ◽  
Open Face ◽  
Vinyl Group ◽  
The University

The sulfate ( + )-didemniserinolipid B 3, isolated from the tunicate Didemnum sp, has an intriguing spiroether core. A key step in the synthesis of 3 reported (Organic Lett. 2007, 9, 5357) by Steven D. Burke of the University of Wisconsin was the selective ring-closing metathesis of 1 to 2. The diol 6 that was used to prepare the ketal 1 was readily prepared from the inexpensive D-mannitol 4. Many other applications can be envisioned for the enantiomerically-pure diol 6 and for the monoacetate and bis acetate that are precursors to it. To set up the metathesis, the β, γ-unsaturated ketone 10 was needed. To this end, the keto phosphonate derived from the addition of the phosphonate anion 8 to the lactone 7 was condensed with phenyl acetaldehyde 9. The derived enone 10 was a 5:1 mixture of β, γ- and α, β-regioisomers. The diol 6 is C2 -symmetrical, but formation of the ketal 1 dissolved the symmetry, with one terminal vinyl group directed toward the styrene double bond, and the other directed away from it. On exposure to the first generation Grubbs catalyst, ring formation proceeded efficiently, to give 2. Williamson coupling with the serine-derived alcohol 11 then gave 12. To establish the secondary alcohol of 13 and so of 3, the more electron rich alkene of 12 was selectively epoxidized, from the more open face. Diaxial opening with hydride then gave 13. With 13 in hand, another challenge of selectivity emerged. The plan had been to attach the ester-bearing sidechain to 13 using alkene metathesis, then hydrogenate. As the side-chain of 3 contained an additional alkene, this had to be present in masked form. To this end, the α-phenylselenyl ester 14 was prepared. Alkene metathesis with 13 proceeded smoothly, this time using the second generation Grubbs catalyst. The unwanted alkene was then removed by reduction with diimide, and the selenide was oxidized to deliver the α, β-unsaturated ester.

The Baran Synthesis of Ingenol

2017 ◽  
Author(s):  
Douglass F. Taber
Keyword(s):  
Claisen Rearrangement ◽  
Secondary Alcohol ◽  
Cyclic Carbonate ◽  
The Other ◽  
Magnesium Bromide ◽  
Pseudomonas Cepacia ◽  
Pinacol Rearrangement ◽  
Pseudomonas Cepacia Lipase ◽  
La Jolla ◽  
Open Face

The early promise for the biological activity of the derivatives of ingenol 3 has been borne out by the clinical efficacy of the derived angelate, recently approved by the US Food and Drug Administration for the treatment of actinic keratosis. Phil S. Baran of Scripps La Jolla envisioned (Science 2013, 341, 878) a route to 3 based on a rearrange­ment of 2, available by the Pauson–Khand cyclization of the allenyl alkyne 1. One of the partners for the preparation of 1 was available following the Sugai (Synlett 1997, 1297) procedure, by the Claisen rearrangement of triethyl orthopro­pionate 5 with the propargyl alcohol 4 to give 6. Reduction delivered a racemic mix­ture of alcohols. On exposure of the mixture to vinyl acetate and Pseudomonas cepacia lipase, the undesired enantiomer was selectively acetylated to 7, leaving residual 8 of high ee. IBX was found by the Scripps group to be effective at oxidizing 8 without racemization. The other component of 1 was prepared from the inexpensive (+)-3-carene 10. Chlorination followed by ozonolysis delivered 11, that was reduced to the enolate, then alkylated with methyl iodide. Exposure to LiHMDS gave a new enolate, that was added to the aldehyde 9 to give 12. Addition of ethynyl magnesium bromide to the now more open face of 12 proceeded with high diastereoselectivity. Selective silylation of the secondary alcohol followed by silylation of the tertiary alcohol set the stage for the Pauson–Khand cyclization. Following the Brummond protocol, 1 was cyclized to 2. Methyl magnesium bro­mide was added, again to the more open face of the ketone, to give a new tertiary alco­hol. Exposure to stoichiometric OsO4 converted the more available alkene to the cis diol, that was protected as its cyclic carbonate 13. A central challenge in the total synthesis of the ingenanes is the construction of the “inside–outside” skeleton. This was achieved by the pinacol rearrangement of 13 with BF3•OEt2, to give 14. All that remained to complete the synthesis was selective oxidation. Allylic oxi­dation with stoichiometric SeO2 installed the secondary alcohol, that was acety­lated to give 15. The other secondary alcohol was then freed, and dehydrated with the Martin sulfurane, to give 16. A last allylic oxidation completed the synthesis of ingenol 3.

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