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Topic: QSPR


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In the News (Mon 7 Dec 09)

  
  QSPR   (Site not responding. Last check: 2007-10-12)
The Quantitative Structure Property Relationship (QSPR) is used in the field of chemistry, and relates bio-physico-chemical properties of chemical compound s to their structures.
It is well known for instance that within a particular family of chemical compounds, especially of organic chemistry, that there are strong correlations between structure and observed properties.
Drug discovery often involves the use of QSPR to identify chemical structures that could have good inhibitory effects on specific targets and have low toxicity (non-specific activity).
www.serebella.com /encyclopedia/article-QSPR.html   (515 words)

  
 QSPR: Studies and its Promises - Features   (Site not responding. Last check: 2007-10-12)
QSPR studies can be suitably utilized at the early stage of clinical trials to be design a better molecule with favourable biological activity and pharmacokinetic character.
There are studies of QSPR on variety of therapeutic categories including barbiturates, sulfomnamides, carbamates, basic drugs, acidic drug etc. for their absorption, distribution, metabolism, elimination, which has led to understand that it is possible to manipulate the PK parameters without muddling with the therapeutic effects.
These changes are predicted by conducting QSPR studies which has paved to the design and synthesis of an effective anti-inflammatory drug, with duration of action lasting 24 hours to 48 hours, which is a boon for an arthritis patients.
www.pharmabiz.com /article/detnews.asp?articleid=11415§ionid=46   (763 words)

  
 Quantitative structure-property relationship - the free encyclopedia   (Site not responding. Last check: 2007-10-12)
The quantitative structure-property relationship (QSPR) is used in the field of
The basic rationale behind the use of QSPR is the fact that there are strong trends.
It is necessary that the predicted variable has been compared with a number of observations made to sufficient accuracy for a variety of pure chemicals belong to the same
www.encyclopedia-of-world-knowledge.com /default.asp?t=QSPR   (232 words)

  
 QSPR Correlation of Glass Transition Temperatures of   (Site not responding. Last check: 2007-10-12)
QSPR CORRELATION OF GLASS TRANSITION TEMPERATURES OF HIGH MOLECULAR WEIGHT POLYMERS
The five parameter QSPR model (see Figure 1) with R
The sum of square roots of hydrogen acceptor surface areas divided by the total surface area of repeating unit quantifies the ability of a polymer to form hydrogen bonds.
osoon.ut.ee /~aks/teesid/sild1.htm   (175 words)

  
 Accelrys
This small screening library was used to develop subsequent QSPR models.
The QSPR models were then used to calculate the Tg and the CA for the remaining polymers in the full set.
These QSPR equations can be used to design focused libraries of polymers with specific combinations of Tg and CA.
www.accelrys.com /reference/cases/studies/reynolds.html   (501 words)

  
 Postgenomic - Books & Papers details
Two QSAR and QSPR models based on signature are compared with models obtained using popular molecular 2D descriptors taken from a commercially available software (Molconn-Z).
While probing signature's QSAR and QSPR performances, we demonstrates that for any given molecule of diameter D, there is a molecular signature of height h
As a consequence of this finding any QSAR or QSPR involving 2D descriptors can be replaced with a relationship involving occurrence number of atomic signatures.
www.postgenomic.com /paper.php?doi=10.1021/ci020345w   (278 words)

  
 QSPR   (Site not responding. Last check: 2007-10-12)
The Quantitative Structure Property Relationship (QSPR) is used in the field of chemistry, and relates bio-physico-chemical properties of chemical compounds to their structures.In biological contexts, these are also called Quantitative Structure ActivityRelationships (QSAR).
Drug discovery often involves the use of QSPR to identifychemical structures that could have good inhibitory effects on specific targets and have low toxicity (non-specific activity).
While many Quantitative Structure Activity Relationships involve analysis of the interactions of a family of small moleculeswith an enzyme or receptor binding site, QSPR can also be used to study interactions between the structural domains of proteins.
www.therfcc.org /qspr-21647.html   (433 words)

  
 Amazon.com: QSPR   (Site not responding. Last check: 2007-10-12)
QSPR to aqueous solubility (lgS"w) of alkyl(1-phenylsulfonyl) cycloalkane-carboxylates using MLSER model and ab initio by Z. Wang, X. Han, and Z. Zhai
QSPR models for physicochemical properties of polychlorinated diphenyl ethers by P. Yang, J. Chen, S. Chen, and X. Yuan (April 15, 2003)
Wavelet neural network-based QSPR for prediction of critical micelle concentration of Gemini surfactants by Z. Kardanpour, B. Hemmateenejad, and T. Khayamian (Feb 28, 2005)
www.amazon.com /s?ie=UTF8&platform=gurupa&keywords=QSPR&search-type=ss&tag=vepoware14-20&index=blended&link_code=qs&page=1   (849 words)

  
 Title page for ETD etd-01062006-171809
Once the affinity coefficient of a target contaminant is calculated from the poly-parameter QSPR and the affinity coefficient of water is calculated from the adsorbent’s oxygen content, a composite contaminant/water affinity coefficient can be obtained for the adsorbate/adsorbent pair of interest.
To enhance the confidence in the predictive powers of the developed QSPRs, a more comprehensive external validation test should be conducted.
Of particular importance would be to assess the importance of specific interactions between polar organic contaminants and oxygen-containing functional groups on the activated carbon surface.
www.lib.ncsu.edu /theses/available/etd-01062006-171809   (637 words)

  
 Water Activated Carbon Organics Adsorption Structure - Property Relationships from Leonardo Journal of Sciences
The MDF QSPR methodology has big potential in finding QSPR models and is proved for adsorption onto activated carbon in water of studied organics.
First step in QSPR modeling using the molecular descriptor family was sketching up the three-dimensional structure of each compound using the HyperChem software [14], software that allows assigning standard bond lengths, bond angles, torsion angles, and stereochemistry.
The best tri-varied MDF QSPR is given by the equation 5, table 3, which has the best cross validation score (over 0.99); thus, this model is the best able to estimate the adsorption.
ljs.academicdirect.org /A05/63_73.htm   (1691 words)

  
 Products Polymer and Composite Consulting, Contract Research, and Software
HTPD will implement a combination of combinatorial modeling algorithms and QSPR techniques to enable its users to perform rapid "reverse engineering" searches over a vast repeat unit library, to look for repeat units that may be expected to provide desired combinations of properties.
Such QSPR are most often developed for families of polymers which are structural variants, by using data measured in the same organization under consistent experimental protocols.
Within their narrower range of applicability, they are often much more accurate (and hence more useful) than "general-purpose" QSPR developed by using data obtained in many different laboratories over a much broader range of polymer structures.
www.polymerexpert.biz /products.html   (572 words)

  
 Directory of open access journals
A newly elaborated set of molecular descriptors is evaluated to determine their usefulness for QSPR studies.
Using a data set containing 180 phosphates and diphosphates, ANN trained with the back propagation and conjugated gradient algorithms are able to predict the refractive index with relatively high accuracy.
The QSPR studies described in this paper provide strong evidence that the tested structural descriptors are useful and effective for the ANN modeling of the phosphates refractive index.
www.doaj.org /abstract?id=100348&toc=y   (198 words)

  
 Chemometrics & Informatics - Your Chemometrics & Informatics Resource
A QSPR (quantitative structure-property relationship) study of the anaerobic biodegradation of chlorophenols could lead to an improvement in the disposal of these potentially carcinogenic industrial waste products.
Each chlorophenol undergoes degradation through subtly different mechanisms, so the team enlisted QSPR to help them untangle the various reaction threads and to reveal any inherent patterns that might offer clues as to how to carry our remediation of waste waters and contaminated soils more effectively.
The result of their analysis of 13 chlorophenols as a training set, with logK values as a dependent variable and 29 chemical descriptors as independent variables, allowed them to produce a PLS model of chlorophenol reductive dechlorination.
www.spectroscopynow.com /coi/cda/detail.cda?id=13809&type=Feature&chId=9&page=1   (308 words)

  
 Polymer - QSPR Module   (Site not responding. Last check: 2007-10-12)
The Dow QSPR methodology relies upon calculating the properties of the repeat units in isolation, and averaging the results to obtain the properties of the polymer.
If one of the QSPR groups 31, 38, 39, 41-43, or 45Þ-48, is present in the polymer together with an adjacent run of methylene (-CH -) groups, then the contribution of each methylene group is dependent upon the distance from the nearest of these functional groups.
The rules that control the identification of QSPR groups are identical for the Dow and the van Krevelen methodologies.
www.esi.umontreal.ca /accelrys/materials/insight400P/polymer/11-QSPR_3.doc.html   (5740 words)

  
 [No title]
In homogeneous catalysis the rate and selectivity of the reaction is often very dependent on the structure of the catalyst.
Unfortunately, Quantitative Structure –; Property Relationships (QSPR) are often very difficult to obtain.
Avantium has embraced the use of descriptor-based QSPR modeling; structures are converted into a large number of molecular descriptors.
www.avantium.com /corporate/services/process-development/qcs-homogenous.htm   (232 words)

  
 QSPR Treatment of the Soil Sorption Coefficients of Organic Pollutants
QSPR Treatment of the Soil Sorption Coefficients of Organic Pollutants
Accordingly, QSPR models were also developed for 14 chemical classes.
The descriptors appearing in these models were discussed as related to the possible interaction mechanisms in soil sorption.
pubs.acs.org /cgi-bin/abstract.cgi/jcisd8/2005/45/i01/abs/ci0498766.html   (261 words)

  
 QSPR Correlation of Glass Transition Temperatures of   (Site not responding. Last check: 2007-10-12)
The descriptors involved are: HOMO - LUMO energy gap, lowest electron-nucleus attraction energy for a carbon atom, partial positively charged surface area, the surface area of hydrogen donor atoms, and the gravitation index.
The QSPR approach was expanded to polymers as well (see Figure 2).
The models are also applicable to not yet synthesized compunds, since they depend only on theoretical descriptors calculated from the molecular structure.
osoon.ut.ee /~aks/teesid/sild2.htm   (153 words)

  
 Infotrieve Online
QSPRs for the prediction of photodegradation half-life of PCBs in n-hexane.
By partial least squares (PLS) regression analysis, a quantitative structure-property relationship (QSPR) model was developed for photodegradation half-life (t1/2) of polychlorinated biphenyls (PCBs) in n-hexane solution under UV irradiation.
The cross-validated value for the optimal QSPR model was 0.589, indicating good predictive capability for log t1/2 values of PCBs in n-hexane.
www4.infotrieve.com /newmedline/detail.asp?NameID=16644556&Session=&searchQuery=Hexanes&count=1057   (177 words)

  
 Solvent Extraction and QSPR of Catecholamines with a Bis(2-ethylhexyl) Hydrogen Phosphate   (Site not responding. Last check: 2007-10-12)
Solvent Extraction and QSPR of Catecholamines with a Bis(2-ethylhexyl) Hydrogen Phosphate
In order to develop an effective separation process for catecholamine (CA), a basic investigation on solvent extraction of dopamine (DA), adrenaline (Ad) and noradrenaline (NA) from hydrochloric acid solution and their stripping is conducted at 30 C employing bis(2-ethylhexyl) hydrogen phosphate (D2EHPA) in chloroform, n- hexane and toluene as the organic diluents.
The quantitative structure property relationship (QSPR) of Kex,CA vlaues for each organic diluent is discussed using molecular modeling with semi-empirical molecular orbital calculations considering the solvent effect.
www.scej.org /ronbun/JCEJe/e32p0076.html   (194 words)

  
 Directory of open access journals
Comparative QSPR Studies with Molecular Connectivity, Molecular Negentropy and TAU Indices.
The TAU scheme is unique in that it unravels specific contributions of functionality, branching, shape and size factors to the physicochemical property or biological activity while other indices give mainly a global contribution of the molecule.
Subsequently, several papers described QSAR and QSPR with TAU index to show the diagnostic potential of the parameter, but much work has not been done on the index.
www.doaj.org /abstract?id=100346&toc=y   (287 words)

  
 Hollas, Boris: On the Redundancy of Topological Indices
Experimental results with chemical graphs support these findings, which are of practical importance for QSAR/ QSPR studies and other applications of topological indices.
Nowadays several hundreds of topological indices are being used in the socalled QSPR (quantitative structure–property relations) and QSAR (quantitative structure–activity relations) studies.
The idea is the following: one tries to construct a simple (usually, a linear) mathematical model that reproduces the experimentally available data, expecting that the same model will correctly (in a statistical sense) predict the same data for not-yet-synthesized compounds.
www.driesen-online.de /gv_hollas_redundancy.htm   (1450 words)

  
 Abstract of IQC paper   (Site not responding. Last check: 2007-10-12)
The theoretical results presented in this work point out that quantitative structure—properties relationslips (QSPR) can be appropriately founded within the theoretical background of quantum mechanics.
In this way, the deducible quantum QSPR (QQSPR) framework and the associated fundamental equation, furnish with a causal backup the structure—properties relationships old problem.
Moreover, they also provide algorithms to obtain in a general manner, up to any approximation level and even from a variational point of view, unbiased and universal causal QSPR models for any chosen quantum object set.
quimica.udg.es /scripts/iqc/artabs.idc?art=414   (94 words)

  
 QSPR / QSAR Studies by Molecular Descriptors -- Book
After an overview of research in topological indices for QSAR/QSPR, chapters cover Wiener-type graph invariants, calculation of molecular descriptors based on various graphical bond orders, graph connectivity indices versus live graph connectivity indices, QSPR/QSAR by graph theoretical descriptors, and the concept of graph mass in molecular graph theory.
The central problem in QSPR (Quantitative Structure-Property Relationship) / QSAR (Quantitative Structure-Activity Relationship) is to convert chemical structures into molecular descriptors that are relevant to a certain physico-chemical property or biological activity.
Although various physico-chemical properties may be subjected to QSPR/QSAR studies, the major application field of these models is drug discovery.
www.bookspec.com /un/1560728590   (281 words)

  
 chem-bla-ics: 1D NMR Spectra do not work in QSPR
Half a year later we concluded that from the data which we started with (48 compounds with binding affinity), no conclusions could be drawn what so ever: no statistically sound models could be build at all.
These sets, all QSPR data sets, did give us models, but all the spectra based models were worse than a Dragon descriptor based model using the same number of variables, without doing any variable selection.
I presented this work at the 7th ICCS in Noordwijkerhout half a year ago, and now got published in the JCIM: DOI 10.1021/ci050282s.
chem-bla-ics.blogspot.com /2006/01/1d-nmr-spectra-do-not-work-in-qspr.html   (304 words)

  
 Internet Electronic Journal of Molecular Design
QSPR Study for the Hydrophobicity of 4-Aryloxy-7-nitrobenzofurazan and 2-Aryloxy-(α-acetyl)-phenoxathiin Derivatives
A quantitative structure-property relationship (QSPR) was established between the experimental R
The QSPR models were validated by the leave-one-out cross validation method.
www.biochempress.com /av05_0237.html   (229 words)

  
 Modeling : Rational Design & QSPR
The underlying assumption in QSPR is that it is possible to predict the properties or performance of compounds by knowing their molecular structures.
This approach allows large libraries of reagents, solvents and catalysts to be virtually screened, while only those molecules that are predicted to perform well need to be synthesized and tested.
Avantium is keen to discuss the use of Rational Design and QSPR for the optimization of any product or process or the possibility of integrating our modeling expertise with the High-throughput Experimentation capabilities of our customers.
www.avantium.com /corporate/services/modeling/rational-design.htm   (263 words)

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