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Träfflista för sökning "WFRF:(Kent P.) srt2:(2000-2004)"

Sökning: WFRF:(Kent P.) > (2000-2004)

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2.
  • Hillier, Ladeana W, et al. (författare)
  • Sequence and comparative analysis of the chicken genome provide unique perspectives on vertebrate evolution
  • 2004
  • Ingår i: Nature. - 0028-0836 .- 1476-4687. ; 432:7018, s. 695-716
  • Tidskriftsartikel (refereegranskat)abstract
    • We present here a draft genome sequence of the red jungle fowl, Gallus gallus. Because the chicken is a modern descendant of the dinosaurs and the first non-mammalian amniote to have its genome sequenced, the draft sequence of its genome--composed of approximately one billion base pairs of sequence and an estimated 20,000-23,000 genes--provides a new perspective on vertebrate genome evolution, while also improving the annotation of mammalian genomes. For example, the evolutionary distance between chicken and human provides high specificity in detecting functional elements, both non-coding and coding. Notably, many conserved non-coding sequences are far from genes and cannot be assigned to defined functional classes. In coding regions the evolutionary dynamics of protein domains and orthologous groups illustrate processes that distinguish the lineages leading to birds and mammals. The distinctive properties of avian microchromosomes, together with the inferred patterns of conserved synteny, provide additional insights into vertebrate chromosome architecture.
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4.
  • Bertilsson, Kent, et al. (författare)
  • The Effect of Different Transport Models in Simulation of High Frequency 4H-SiC and 6H-SiC Vertical MESFETs
  • 2001
  • Ingår i: Solid-State Electronics. - 0038-1101 .- 1879-2405. ; 45:5, s. 645-653
  • Tidskriftsartikel (refereegranskat)abstract
    • A full band Monte Carlo (MC) study of the high frequency performance of a 4H-SiC Short channel vertical MESFET is presented. The MC model used is based on data from a full potential band structure calculation using the local density approximation to the density functional theory. The MC results have been compared with simulations using state of the art drift-diffusion and hydrodynamic transport models. Transport parameters such as mobility, saturation velocity and energy relaxation time are extracted from MC simulations
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5.
  • Lindholm, Lars H, et al. (författare)
  • Relation between drug treatment and cancer in hypertensives in the Swedish Trial in Old Patients with Hypertension 2: a 5-year, prospective, randomised, controlled trial
  • 2001
  • Ingår i: The Lancet. - 1474-547X. ; 358, s. 539-
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND: Is cancer related to hypertension and blood pressure? Do antihypertensive drugs promote cancer? Do antihypertensive drugs protect against cancer? We previously analysed the frequency of cardiovascular mortality and morbidity in elderly people who participated in the Swedish Trial in Old Patients with Hypertension 2 (STOP-Hypertension-2). We have also looked at the frequency of cancer in these patients. METHODS: We randomly assigned 6614 elderly patients with hypertension (mean age 76 years, median time of follow-up 5.3 years) to one of three treatment strategies: conventional drugs (diuretics or b-blockers), calcium antagonists, or ACE inhibitors. We matched the patients to the Swedish Cancer Registry and compared our findings with expected values based on age, sex, and calendar-year-specific reference frequencies for the general Swedish population. We also compared the number of cancers between the three treatment groups. FINDINGS: At baseline, 607 (9%) patients had previous malignant disease. Diagnoses were closely similar to the distribution of cancer types that might be seen in elderly patients. During follow-up, there were 625 new cases of cancer in 590 patients. The frequency of cancer did not differ significantly between the treatment strategies, including all cancers and those at individual sites. The standardised incidence ratios (SIRs) for all cancers were also close to unity: 0.92 (95% CI 0.80-1.06) for conventional drugs, 0.96 (0.83-1.10) for calcium antagonists, and 0.99 (0.86-1.13) for ACE inhibitors. INTERPRETATIONS: No difference in cancer risk was seen between patients randomly assigned to conventional drugs, calcium antagonists, or ACE inhibitors. Thus, the general message to the practising physician is that more attention should be given to getting the blood pressure down than to the risk of cancer.
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6.
  • Seppet, E. K., et al. (författare)
  • Functional complexes of mitochondria with MgATPase of myofibrils and sarcoplasmic reticulum in muscle cells
  • 2001
  • Ingår i: Biochimica et Biophysica Acta - Bioenergetics. - Amsterdam : Elsevier. - 0005-2728 .- 1879-2650. ; 1504:2-3, s. 379-395
  • Tidskriftsartikel (refereegranskat)abstract
    • Regulation of mitochondrial respiration in situ in the muscle cells was studied by using fully permeabilized muscle fibers and cardiomyocytes. The results show that the kinetics of regulation of mitochondrial respiration in situ by exogenous ADP are very different from the kinetics of its regulation by endogenous ADP. In cardiac and m. soleus fibers apparent Km for exogenous ADP in regulation of respiration was equal to 300–400 µM. However, when ADP production was initiated by intracellular ATPase reactions, the ADP concentration in the medium leveled off at about 40 µM when about 70% of maximal rate of respiration was achieved. Respiration rate maintained by intracellular ATPases was suppressed about 20–30% during exogenous trapping of ADP with excess pyruvate kinase (PK, 20 IU/ml) and phosphoenolpyruvate (PEP, 5 mM). ADP flux via the external PK+PEP system was decreased by half by activation of mitochondrial oxidative phosphorylation. Creatine (20 mM) further activated the respiration in the presence of PK+PEP. It is concluded that in oxidative muscle cells mitochondria behave as if they were incorporated into functional complexes with adjacent ADP producing systems – with the MgATPases in myofibrils and Ca,MgATPases of sarcoplasmic reticulum.
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8.
  • Wiberg, Kent, et al. (författare)
  • Determination of the content and identity of lidocaine soluions with UV-visible spectroscopy and multivariate calibration
  • 2001
  • Ingår i: The Analyst. - : Royal Society of Chemistry (RSC). - 0003-2654 .- 1364-5528. ; 126:7, s. 1142-1148
  • Tidskriftsartikel (refereegranskat)abstract
    • A method is proposed for the determination of the content and identity of the active compound in pharmaceutical solutions by means of ultraviolet-visible (UV–Vis) spectroscopy, orthogonal signal correction (OSC) and multivariate calibration with soft independent modelling of class analogy (SIMCA) classification and partial least squares (PLS) regression. The content was determined with PLS regression and the identity with PLS regression and SIMCA classification. The method was tested on the local anaesthetic compound lidocaine. For the validation, external test sets of both manufactured sample solutions and samples from a stability study were used. For comparison with this new method, liquid chromatography was used as a reference method. The results show that in respect of accuracy, precision and repeatability, the new method is comparable to the reference method. The main advantage over liquid chromatography is the much shorter time of analysis and the simpler analytical procedure. An estimate of the analysis time saved with the proposed method compared with using liquid chromatography, together with practical considerations, is given.
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9.
  • Wiberg, Kent, et al. (författare)
  • Parallel factor analysis of HPLC-DAD data for binary mixtures of lidocaine and prilocaine with different levels of separation
  • 2004
  • Ingår i: Analytica Chimica Acta. - : Elsevier BV. - 0003-2670 .- 1873-4324. ; 514:2, s. 203-209
  • Tidskriftsartikel (refereegranskat)abstract
    • A set of 17 samples containing a constant amount of lidocaine (667 muM) and a decreasing amount of prilocaine (667-0.3 muM) was analysed by LC-DAD at three different levels of separation, followed by parallel factor analysis (PARAFAC) of the data obtained. In Case 1 no column was connected, the chromatographic resolution (R-s) therefore being zero, while Cases 2 and 3 had partly separated peaks (R-s = 0.7 and 1.0). The results showed that in Case 1, analysed without any separation, the PARAFAC decomposition with a model consisting of two components gave a good estimate of the spectral and concentration profiles of the two compounds. In Cases 2 and 3, the use of PARAFAC models with two components resolved the underlying chromatographic, spectral and concentration profiles. The loadings related to the concentration profile of prilocaine were used for regression and prediction of the prilocaine content. The results showed that prediction of prilocaine content was possible with satisfactory prediction (RMSEP < 0.01). This study shows that PARAFAC is a powerful technique for resolving partly separated peaks into their pure chromatographic, spectral and concentration profiles, even with completely overlapping spectra and the absence or very low levels of separation.
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10.
  • Wiberg, Kent, et al. (författare)
  • Peak purity determination with principal component analysis of high-performance liquid chromatography-diode array detection data
  • 2004
  • Ingår i: Journal of Chromatography A. - : Elsevier BV. - 0021-9673 .- 1873-3778. ; 1029:1-2, s. 13-20
  • Tidskriftsartikel (refereegranskat)abstract
    • A method is proposed for the determination of chromatographic peak purity by means of principal component analysis (PCA) of high-performance liquid chromatography with diode array detection (HPLC–DAD) data. The method is exemplified with analysis of binary mixtures of lidocaine and prilocaine with different levels of separation. Lidocaine and prilocaine have very similar spectra and the chromatograms used had substantial peak overlap. The samples analysed contained a constant amount of lidocaine and a minor amount of prilocaine (0.02–2 conc.%) and hence the focus was on determining the purity of the lidocaine peak in the presence of much smaller levels of prilocaine. The peak purity determination was made by examination of relative observation residuals, scores and loadings from the PCA decomposition of DAD data over a chromatographic peak. As a reference method, the functions for peak purity analysis in the chromatographic data system used (Chromeleon) were applied. The PCA method showed good results at the same level as the detection limit of baseline-separated prilocaine, outperforming the methods in Chromeleon by a factor of ten. There is a discussion of the interpretation of the result, with some comparisons with evolving factor analysis (EFA). The main advantage of the PCA method for determination of peak purity over methods like EFA lies in its simplicity, short time of calculation and ease of use.
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11.
  • Wiberg, Kent, et al. (författare)
  • Rapid determination of lidocaine solutions with non-column chromatographic diode array UV spectroscopy and multivariate calibration
  • 2003
  • Ingår i: Journal of Pharmaceutical and Biomedical Analysis. - 0731-7085 .- 1873-264X. ; 30:5, s. 1575-1586
  • Tidskriftsartikel (refereegranskat)abstract
    • A new method for the rapid determination of pharmaceutical solutions is proposed. A conventional HPLC system with a Diode Array Detector (DAD) was used with no chromatographic column connected. As eluent, purified water (Milli Q) was used. The pump and autosampler of the HPLC system were mainly utilised as an automatic and convenient way of introducing the sample into the DAD. The method was tested on the local anaesthetic compound lidocaine. The UV spectrum (245–290 nm) from the samples analysed in the detector was used for multivariate calibration for the determination of lidocaine solutions. The content was determined with PLS regression. The effect on the predictive ability of three factors: flow, data-collection rate and rise time as well as two ways of exporting a representative UV spectrum from the DAD file collected was investigated by means of an experimental design comprising 11 experiments. For each experiment, 14 solutions containing a known content of lidocaine were analysed (0.02–0.2 mg ml−1). From these 14 samples two calibration sets and two test sets were made and as the response in the experimental design the Root Mean Square Error of Prediction (RMSEP) values from the predictions of the two test sets were used. When the factor setting giving the lowest RMSEP was found, this setting was used when analysing a new calibration set of 12 lidocaine samples (0.1–0.2 mg ml−1). This calibration model was validated by two external test sets, A and B, analysed on separate occasions for the evaluation of repeatability (test set A) and determination over time (test set B). For comparison, the reference method, liquid chromatography, was also used for analysis of the ten samples in test set B. This comparison of the two methods was done twice on different occasions. The results show that in respect of accuracy, precision and repeatability the new method is comparable to the reference method. The main advantages compared with liquid chromatography are the much shorter time of analysis (<30 s) as well as the automatic and simple analytical procedure and the low consumption of organic solvents.
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12.
  • Wiberg, Kent, et al. (författare)
  • Simultaneous determination of albumin and immunoglobulin G with fluorescence spectroscopy and multivariate calibration
  • 2004
  • Ingår i: Talanta. - : Elsevier BV. - 0039-9140 .- 1873-3573. ; 62:3, s. 567-574
  • Tidskriftsartikel (refereegranskat)abstract
    • A method is proposed for the simultaneous determination of albumin and immunoglobulin G (IgG1) with fluorescence spectroscopy and multivariate calibration with partial least squares regression (PLS). The influence of some instrumental parameters were investigated with two experimental designs comprising 19 and 11 experiments, respectively. The investigated parameters were excitation and emission slit, detection voltage and scan rate. When a suitable instrumental setting had been found, a minor calibration and test set were analysed and evaluated. Thereafter, a larger calibration of albumin and IgG1 was made out of 26 samples (0–42 μg ml−1 albumin and 0–12.7 μg ml−1 IgG1). This calibration was validated with a test set consisting of 14 samples in the same concentration range. The precision of the method was estimated by analysing two test set samples for six times each. The scan modes tested were emission scan and synchronous scan Δ60 nm. The results showed that the method could be used for determination of albumin and IgG1 (albumin, root mean square error of prediction (RMSEP) <2, relative standard error of prediction (RSEP) <6% and IgG1, RMSEP <1, RSEP <8%) in spite of the overlapping fluorescence of the two compounds. The estimated precision was relative standard deviation (R.S.D.) <1.7%. The method was finally applied for the analysis of some sample fractions from an albumin standard used in affinity chromatography.
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13.
  • Wiberg, Kent, et al. (författare)
  • Use of control sample for estimation of prediction error in multivariate determination of lidocaine solutions with non-column chromatographic diode array UV spectroscopy
  • 2003
  • Ingår i: Journal of Pharmaceutical and Biomedical Analysis. - 0731-7085 .- 1873-264X. ; 33:5, s. 859-869
  • Tidskriftsartikel (refereegranskat)abstract
    • The aim of this study was to investigate the ability of a control sample, of known content and identity, to diagnose and correct errors in the predictions when the same multivariate calibration model was used for analysis of new samples over time. A calibration set consisting of 16 samples with a known content of lidocaine was analysed and two external test sets, A and B, were used for the validation. Test set A contained 15 samples with different concentrations of lidocaine and test set B contained three samples with different lidocaine content, which were analysed six times in order to obtain a measure of repeatability. The multivariate calibration was done with PLS regression on UV spectra collected between 245 and 290 nm. A representative UV spectrum was exported from the collected DAD files by two methods, average spectrum over the whole file and average spectrum over the sample plug. Test set A was analysed further on another three occasions together with a control sample. The results showed that the control sample could be used to give a diagnosis and estimate of the prediction error. Moreover, the measured prediction error of the control sample could also be used to correct the predictions, thereby reducing the prediction error. Finally, some practical considerations regarding use of the proposed DAD method with a control sample are presented. The procedure suggested could lead to an efficient analytical approach where the same calibration model could be used over time without recalibration, which may be attractive in industrial quality control or screening analysis in pharmaceutical research.
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