Über die Anwendung der IR-Spektroskopie zur quantitativen Bestimmung von Fetten mit Doppelbindungen in trans-Form

1964 ◽  
Vol 200 (2) ◽  
pp. 152-153
Author(s):  
Gisela Peters
Keyword(s):  
Trans Form ◽  
In Trans

General Properties

2015 ◽  
Author(s):  
James E. Mark ◽  
Dale W. Schaefer ◽  
Gui Lin
Keyword(s):  
Energy Difference ◽  
Van Der Waals Interactions ◽  
Polymer Science ◽  
Trans Form ◽  
Bond Angles ◽  
Coulombic Interactions ◽  
Interest Force ◽  
Repeat Units ◽  
In Trans ◽  
Semi Empirical

Many of the properties of the polysiloxanes have been tabulated in handbooks of polymer science and engineering. Recent work has included the stretching of polydimethylsiloxane (PDMS) chains, in some cases to their rupture points. The nature of the bonding in siloxane molecules has been of long-standing interest. Force fields for calculations of PDMS properties have been revised over the years and are now at an advanced state of development. Some of the simplest approaches employ the methods of molecular mechanics. Most of the experimental results have been obtained on solutions of polysiloxanes in thermodynamically good solvents. The first member of this series, poly(dimethylsiloxane) (PDMS), [–Si(CH3)2O–]x, has been studied extensively with regard to its configuration-dependent properties. PDMS (figure 2.1) is very similar in structure to the polyphosphate chain in that the successive bond angles are not equal. The Si–O bond length in polysiloxanes is 1.64 Å, and bond angles at the Si and O atoms are 110 and 143°, respectively. This inequality of bond angles causes the all-trans form of the molecule (with rotational angles ϕ = 0°) to form a closed structure after approximately eleven repeat units. The torsional barrier for rotations about the skeletal bonds is very low, which accounts for the high dynamic flexibility and low glasstransition temperature of the PDMS chain. Not surprisingly, low temperature properties are superb. Trans states are of lower energy than gauche states (ϕ = ±120°) in the PDMS chain. This conformational preference may arise from favorable van der Waals interactions between pairs of CH3 groups separated by four bonds in trans states. This factor is apparently more important than favorable coulombic interactions between oppositely charged Si and O atoms separated by three bonds, which are larger in gauche states because of the reduced distance. Comparisons between experimental and theoretical values of various configuration-dependent properties, however, yield a value for this energy difference that is significantly larger than that obtained from the semi-empirical calculations of interactions between nonbonded atoms.

scholarly journals Invitro Photo-Controlled Drug Release System Based on Amphiphilic Linear-Dendritic Diblock Copolymers; Self-Assembly Behavior and Application as Nanocarrier

2011 ◽  
Vol 14 (2) ◽  
pp. 162 ◽  
Author(s):  
Hassan Namazi ◽  
Saeed Jafarirad
Keyword(s):  
Diblock Copolymers ◽  
Uv Light ◽  
Drug Carrier ◽  
In Vitro Release ◽  
Simple Type ◽  
Release Behavior ◽  
Trans Form ◽  
Ability To Act ◽  
Micellar Aggregates ◽  
In Trans

Purpose. A simple type of photoresponsive amphiphilic linear-dendritic diblock copolymer has been synthesized and investigated for its ability to act as a drug carrier. These structures contain hydrophilic polyethylene oxide monomethyl ether (PEOM) as hydrophilic block and carbosiloxane dendritic branches as hydrophobic block grafted by two and six Magneson II as azo chromophore, PEOM-Azo, 2 and PEOM-Azo, 6 respectively. Self-assembling of the amphiphilic macromolecules of PEOM-Azo, 2 and PEOM-Azo, 6, briefly were represented as PEOM-Azo [2, 6], leads to the formation of their micellar aggregates in aqueous media. Method. Their micellar properties such as critical micelle concentration (CMC), aggregation number and thereby total numbers of azo-groups in each micellar aggregates were determined. Also, they were characterized by TEM, SEM and DLS. Results. The unloaded aggregates examined under UV light (366 nm), which were observed to be smaller than 300 nm. The release patterns of the encapsulated drug molecule from these aggregates were investigated as regulated by the PEOM-Azo [2, 6] systems in trans and cis forms. Conclusion. A comparison of the release behavior of the loaded PEOM-Azo [2, 6] systems indicated that the release rate of the encapsulated active molecules from the carriers was slower when the azo moieties were in trans form as compared to that the azo in the cis form. The in vitro release behavior of drug from these polymeric systems represents potential of the carriers for controlled drug delivery. This article is open to POST-PUBLICATION REVIEW. Registered readers (see “For Readers”) may comment by clicking on ABSTRACT on the issue’s contents page.

Author response for "TIM-3 and CEACAM1 do not interact in cis and in trans"

2020 ◽  
Author(s):  
Annika De Sousa Linhares ◽  
Florian Kellner ◽  
Sabrina Jutz ◽  
Gerhard J. Zlabinger ◽  
Hans-Joachim Gabius ◽  
...  
Keyword(s):  
Author Response ◽  
In Trans ◽  
In Cis

Fibrinolytic Activity of Cerebro-Spinal Fluid and the Development of Artificial Cerebral Haematomas in Dogs

1969 ◽  
Vol 21 (02) ◽  
pp. 294-303 ◽  
Author(s):  
H Mihara ◽  
T Fujii ◽  
S Okamoto
Keyword(s):  
Cerebrospinal Fluid ◽  
Carboxylic Acid ◽  
Fibrinolytic Activity ◽  
Clinical Implications ◽  
Trans Form ◽  
Plate Method ◽  
Blood Samples ◽  
Fibrin Plate ◽  
The Brain

SummaryBlood was injected into the brains of dogs to produce artificial haematomas, and paraffin injected to produce intracerebral paraffin masses. Cerebrospinal fluid (CSF) and peripheral blood samples were withdrawn at regular intervals and their fibrinolytic activities estimated by the fibrin plate method. Trans-form aminomethylcyclohexane-carboxylic acid (t-AMCHA) was administered to some individuals. Genera] relationships were found between changes in CSF fibrinolytic activity, area of tissue damage and survival time. t-AMCHA was clearly beneficial to those animals given a programme of administration. Tissue activator was extracted from the brain tissue after death or sacrifice for haematoma examination. The possible role of tissue activator in relation to haematoma development, and clinical implications of the results, are discussed.

Resection Control in Trans-sphenoidal Surgery of Pituitary Macroadenoma by Intraoperative High-Field MRI

Skull Base ◽  
2005 ◽  
Vol 15 (S 2) ◽  
Author(s):  
Boris von Keller ◽  
R. Fahlbusch ◽  
O. Ganslandt ◽  
C. Nimsky
Keyword(s):  
High Field ◽  
Pituitary Macroadenoma ◽  
High Field Mri ◽  
Resection Control ◽  
In Trans

Internal Comparison of Open Microscopic versus Endoscopic Approach in Trans-sphenoidal Surgery

Skull Base ◽  
2009 ◽  
Vol 19 (03) ◽  
Author(s):  
Abdulrazag Ajlan ◽  
Anthony Zeitouni ◽  
Denis Sirhan
Keyword(s):  
Endoscopic Approach ◽  
In Trans ◽  
Internal Comparison

Our experiences in Trans-Obturator Tape surgery after performing 150 cases

2007 ◽  
Vol 148 (35) ◽  
pp. 1649-1655
Author(s):  
Roland Csorba ◽  
Rudolf Lampé ◽  
Dezső Simó ◽  
György Bacskó ◽  
Róbert Póka
Keyword(s):  
In Trans

Európában a felnőtt nők közel 30 százaléka szenved a vizelet-visszatartás zavarától. A néhány éve megjelent Trans-Obturator Tape (TOT) műtét egy újabb lehetőséget ad a stresszinkontinencia műtéti gyógyítására. Betegek és módszerek: A kivizsgálás részletes anamnézisfelvételből, stressz- és Q-tip-tesztet is magában foglaló, általános és nőgyógyászati fizikális vizsgálatból, illetve a QUID- (The Questionnaire for Urinary lncontinence Diagnosis) kérdőív kitöltéséből állt. Nem egyértelmű esetekben urodinámiás vizsgálat történt. A szerzők százötven betegen végeztek Trans-Obturator Tape beültetést. A műtét eredményességének értékelését szintén QUID-kérdőívek segítségével végezték. Eredmények: A betegek átlagéletkora 50,8 év volt (SD = 8,64). 69 páciensnek (46%) volt tisztán stresszinkontinenciája, 33 betegnek (22%) késztetéses inkontinenciája, míg 48 esetben (32%) stresszdominanciával kevert inkontinenciát mutattak ki. Az átlagos követési idő 16 hónap (4–26 hónap) volt. A stresszinkontinencia átlagos preoperatív súlyossági pontértéke 11,78, az urge-komponensé 6,63 volt. Az átlagos műtéti idő 25 perc volt. 150 műtét kapcsán szövődményt 4 esetben észleltek. 12 betegnek volt szüksége katéter viselésére 24 órán túl, a leghosszabb katéterezési idő 5 nap volt. Az átlagos ápolási idő 4,76 nap (SD = 0,8) volt. A posztoperatív kérdőívek elemzésekor a stresszkomponensre vonatkozó átlagos súlyossági pont 2,22, az urge-komponensé 2,59 volt. Az elégedettségi felmérésben 46 beteg nagyon jónak (47,4%), 39 jónak (40,2%), 7 közepesnek (7,2%), 3 gyengének (3,1%), 2 beteg pedig eredménytelennek (2,1%) ítélte meg a beavatkozást. Következtetések: A módszer avatott kezekben kiemelkedő hatékonyságú, minimálinvazív, gyors műtét, mely rövid kórházi ápolással és kevés szövődménnyel jár.

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