SEARCH · PubMed Health

Results for “Generation mean analysis”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 757 records · Page 42Linked to original sources

PubMed2004

Growth centiles for Omani premature infants born at 26 weeks of gestation.

OBJECTIVE: The present growth chart used in the Sultanate of Oman does not contain centile measurements for infants born at 26-weeks of gestation. With the increased survival of these premature infants, there is a growing need to develop such a chart. The present study was conducted with the aim to look at the anthropometric measurements (weight, length and head circumference) of Omani premature infants born at 26-weeks of gestation and to develop centile charts for these measurements. METHODS: The study was conducted at the Special Care Baby Unit (SCBU) of the Royal Hospital, one of the major perinatal institutions in Muscat, Oman. A computerized database is maintained for all the admissions from 1996. We extracted the required anthropometric data for all 26-week gestation premature Omani infants admitted to SCBU from January 1996 to November 2003. A total of 49 babies were admitted during that period. Out of these, 43 had complete information on the growth parameters, including birth weight, length and head circumference. These parameters were noted down and by using the statistical package, an analysis was performed to get the normal distribution curve. By using the Microsoft Excel program, graphs were generated for all the 3 growth parameters. RESULTS: The mean birth weight for the premature infants born at 26-week gestation was noted to be 908 +/- 156 grams, with length and head circumference of 33.5 +/- 2.5 and 24.5 +/- 1.7 centimeters. The normal distribution curve was obtained with minimal skewing. CONCLUSION: We were able to generate centile charts of the anthropometric measurements for Omani infants born at 26-weeks of gestation. The next step is to collect the national data from other institutions in Oman and then incorporate it into the present growth chart to make the charts more valid, reliable and applicable.

Anthropometry↗

PubMed1978

Cytocidal and cytostatic ability of Corynebacterium liquefaciens in mouse squamous cell carcinoma in vivo.

The cytostatic and cytocidal action of Corynebacterium liquefaciens was studied in a mouse squamous cell carcinoma in vivo. Kinetic analysis of tumor cells 4 and 8 days after a single i.p. dose of 2.0 mg C. liquefaciens showed a marked prolongation of the mean cell generation time (TG). This prolongation affected most the G1 and, to a lesser extent, the S phases of the cell cycle. The tumor growth factor was decreased, and the mean value of the cell loss factor was increased. Assays to determine the number of tumor cells needed to produce the tumor in one-half of the transplant recipients showed that peritoneal exudate cells collected from mice given injections of C. liquefaciens exerted tumor cell killing that depended on the peritoneal exudate cell tumor:cell ratio. This cell killing was not found with peritoneal exudate cells from normal or proteose peptone-treated mice.

Animals↗

PubMed2001

Fourier transform infrared quantitative analysis of sugars and lignin in pretreated softwood solid residues.

Hydrolysates were obtained from dilute sulfuric acid pretreatment of whole-tree softwood forest thinnings and softwood sawdust. Mid-infrared (IR) spectra were obtained on sample sets of wet washed hydrolysates, and 45 degrees C vacuum-dried washed hydrolysates, using a Fourier transform infrared (FTIR) spectrophotometer equipped with a diamond-composite attenuated total reflectance (ATR) cell. Partial least squares (PLS) analysis of spectra from each sample set was performed. Regression analyses for sugar components and lignin were generated using results obtained from standard wet chemical and high-performance liquid chromatography methods. The correlation coefficients of the predicted and measured values were >0.9. The root mean square standard error of the estimate for each component in the residues was generally within 2 wt% of the measured value except where reported in the tables. The PLS regression analysis of the wet washed solids was similar to the PLS regression analysis on the 45 degrees C vacuum-dried sample set. The FTIR-ATR technique allows mid-IR spectra to be obtained in a few minutes from wet washed or dried washed pretreated biomass solids. The prediction of the solids composition of an unknown washed pretreated solid is very rapid once the PLS method has been calibrated with known standard solid residues.

Biomass↗

PubMed1997

Three-dimensional finite element analysis of the retention of fixed partial dentures.

Four three-dimensional mathematical models were generated, each representing a three-unit fixed partial denture. The second premolar and second molar were used as abutments. Different associations of dental support preparation were tested. A 500-N axial load was applied to the pontic. Strains were analysed for each dental support by means of a three-dimensional finite element analysis technique. The results showed that the greatest strains were observed on the weaker abutment, the premolar. The cervical margin facing the edentulous area is affected most, regardless of the model or the dental support. The greater the dento-prosthetic differential surface between the two dental supports (thus the greater the retention differential) the higher the risk of unsealing.

Bicuspid↗

PubMed1993

Deterministic chaos and the first positive Lyapunov exponent: a nonlinear analysis of the human electroencephalogram during sleep.

Under selected conditions, nonlinear dynamical systems, which can be described by deterministic models, are able to generate so-called deterministic chaos. In this case the dynamics show a sensitive dependence on initial conditions, which means that different states of a system, being arbitrarily close initially, will become macroscopically separated for sufficiently long times. In this sense, the unpredictability of the EEG might be a basic phenomenon of its chaotic character. Recent investigations of the dimensionality of EEG attractors in phase space have led to the assumption that the EEG can be regarded as a deterministic process which should not be mistaken for simple noise. The calculation of dimensionality estimates the degrees of freedom of a signal. Nevertheless, it is difficult to decide from this kind of analysis whether a process is quasiperiodic or chaotic. Therefore, we performed a new analysis by calculating the first positive Lyapunov exponent L1 from sleep EEG data. Lyapunov exponents measure the mean exponential expansion or contraction of a flow in phase space. L1 is zero for periodic as well as quasiperiodic processes, but positive in the case of chaotic processes expressing the sensitive dependence on initial conditions. We calculated L1 for sleep EEG segments of 15 healthy men corresponding to the sleep stages I, II, III, IV, and REM (according to Rechtschaffen and Kales). Our investigations support the assumption that EEG signals are neither quasiperiodic waves nor a simple noise. Moreover, we found statistically significant differences between the values of L1 for different sleep stages.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed2002

Performance evaluation of the Precision PCx point-of-care blood glucose analyzer using discriminant ratio methodology.

Point-of-care glucose testing needs to be integrated into a laboratory information system to provide continuous care. Selecting a particular glucose monitoring system is based on both analytical performance and on user's preference. We evaluated accuracy, performance and regulatory compliance of the Precision PCx glucose analyzer (Abbott), with automatic download into a central station, for remote quality control (QC) management and automatic upgrading. We used the discriminant ratio (DR) methodology, which determines the DR of a test (e.g. the ratio between the underlying SD and the within-subject SD), and compares it to that of another test allegedly measuring the same parameter. Accuracy was evaluated by Clarke's error grid method. Seven hundred and ninety four blood samples were taken from 22 diabetic patients, combined with two capillary blood samples: one for analysis by reference method and the second for PCx analysis. Linear regression analysis revealed, over a 2.1 to 26.9 mmol/l glucose concentration range, a correlation coefficient of 0.963, an intercept of 0.7 mmol/l and a slope of 0.851. Mean difference between meter-generated results and the reference method was -7.1+/-10.8%. Between-run imprecision for PCx using Abbott's controls at low and mid-low concentrations was 5.4 and 3.8%, respectively. Clarke's error grid did not show any clinical impact related to difference between methods. DRs were of similar magnitude using both methods. Nursing staff found PCx easy for everyday use. Our data show that PCx results agree with those obtained with the reference method, as shown by lack of significant difference in DRs, and by excellent correlation.

Blood Glucose↗

PubMed2003

A comparison of the wavelet and short-time fourier transforms for Doppler spectral analysis.

Doppler spectrum analysis provides a non-invasive means to measure blood flow velocity and to diagnose arterial occlusive disease. The time-frequency representation of the Doppler blood flow signal is normally computed by using the short-time Fourier transform (STFT). This transform requires stationarity of the signal during a finite time interval, and thus imposes some constraints on the representation estimate. In addition, the STFT has a fixed time-frequency window, making it inaccurate to analyze signals having relatively wide bandwidths that change rapidly with time. In the present study, wavelet transform (WT), having a flexible time-frequency window, was used to investigate its advantages and limitations for the analysis of the Doppler blood flow signal. Representations computed using the WT with a modified Morlet wavelet were investigated and compared with the theoretical representation and those computed using the STFT with a Gaussian window. The time and frequency resolutions of these two approaches were compared. Three indices, the normalized root-mean-squared errors of the minimum, the maximum and the mean frequency waveforms, were used to evaluate the performance of the WT. Results showed that the WT can not only be used as an alternative signal processing tool to the STFT for Doppler blood flow signals, but can also generate a time-frequency representation with better resolution than the STFT. In addition, the WT method can provide both satisfactory mean frequencies and maximum frequencies. This technique is expected to be useful for the analysis of Doppler blood flow signals to quantify arterial stenoses.

Algorithms↗

PubMed2001

Pharmacokinetics of echocontrast agent infusion in a dog model.

Ultrasound contrast agents (UCAs) have a distinct diagnostic impact on transcranial Doppler (TCD) and duplex sonography. In addition to the properties of the UCA and ultrasound imaging modes, the duration of contrast enhancement depends on the administration mode. Infusion of UCAs may be appropriate for prolonging the diagnostically useful time of elevated Doppler intensity. Five sedated dogs were investigated by TCD during infusion with SonoVue, a new UCA consisting of sulfur hexafluoride microbubbles. The infusion rate was varied, and the time-intensity curves were analyzed. Infusion rate of 70 ml/h provided a stable mean level of increased Doppler intensity up to 24 to 26 dB over baseline, whereas a rate of 35 ml/h did not result in a stable plateau (range 8-19 dB over baseline [5 minutes after starting time]). The maximum increases in Doppler mean intensity (18.2 dB [35 ml/h] and 25.6 dB [70 ml/h]) were significantly different (P = .025). Pharmacokinetic analysis of SonoVue during inflow (by exponential functional fitting of the time-mean intensity curves) and elimination (by linear regression analysis) revealed no dose-related differences. This study demonstrated a dose-dependent level of increased Doppler mean intensity within the brain circulation during infusion of SonoVue. Unlike the bell-shaped course of Doppler signal enhancement seen after bolus injection, infusion generates a stable plateau, which is an important prerequisite for more advanced contrast applications.

Analysis of Variance↗

PubMed1998

Consanguinity in question in two patients with congenital adrenal hyperplasia who bear an identical first and last name--second look.

Two patients with identical first and last name, both suffering from Congenital Adrenal Hyperplasia due to 21-hydroxylase deficiency, were investigated in our endocrine outpatient unit. The families of the two girls did not know of each other's existence. Although paternal ancestors were identified up to the 11th and 9th previous generations, respectively, and a common area of origin, roughly 50 km apart, in the northwestern part of the Czech Republic (formerly Austrian Silesia) was established, no common ancestor was found. The patients' respective paternal CYP 21B allele was identical. However, by means of analysis of class I-and class II-HLA regions in both patients and their respective parents no common paternal haplotype was established. In order to still postulate consanguinity by the same paternal haplotype it is necessary to assume that two recombinations in the HLA region must have occurred. The probability that these two events have taken place within the past 11 generations is 0.11%.

Adolescent↗

PubMed1997

The utilization of automated ST segment analysis in the determination of myocardial ischemia.

Perioperative cardiac morbidity is a recognized complication of anesthesia and surgery. Morbidity includes myocardial infarction, new onset of unstable angina, congestive heart failure, and arrhythmias. Almost one third of all patients undergoing noncardiac surgery may be at increased risk of cardiac complications by virtue of age, coronary artery disease (CAD), or presence of two or more risk factors for CAD. Although postoperative ischemia has been identified as a significant risk factor for morbidity, automated ST segment analysis systems available with the new generation bedside monitors have not been used to identify ischemic episodes in patients recovering from anesthesia. Twenty-eight patients, age 41 to 80 years, were monitored in the postanesthesia care unit for ST segment changes (mean monitoring period, 97 minutes). Four patients had ischemic episodes from 7 to 44 minutes, and two of these patients had subsequent postoperative morbidity. All episodes were clinically silent. Automated ST segment analysis is an easily used technology that shows promise as a means of early detection of clinically silent perioperative myocardial ischemia.

Adult↗

PubMed2003

[Analysis of physiologic and abnormal pictures of uterine cervix by means of infrared thermography].

RATIONALE FOR THE STUDY: Diagnosis of the uterine cervix lesions remains a key element of the women's health care especially in the context of the cervical carcinoma prophylaxis. The infrared mapping constitutes a new generation biophysical diagnostic method of potential application in medicine. OBJECTIVE: The study was planned to analyze uterine cervix thermograms in both physiology and pathology of this organ. An attempt was made to establish the standard thermographic pattern of the portion. MATERIAL AND METHODS: The study population consisted of 51 women aged from 20 do 70 years. In total, 109 thermographic patterns were analyzed by the computer processing of the thermovision data. In order to establish a physiologic standard, 14 thermograms of the normal cervix were analyzed in detail. Furthermore, thermograms of such cervical lesions as endocervical polyp (3 patients), erosion (PAP II) (11 cases), CIN I-III (9 patients) and invasive cancer (6 patients) were studied. The diagnosis was based on clinical, cytologic and colposcopic criteria as well as on the pathology report. The infrared camera AGEMA AGA-880 and the specialized software was used. The measurements were done in a standardized climatic environment. RESULTS: Comparisons between the studied groups revealed significant differences between invasive cervical cancer and benign lesions or healthy cervix. Significant were also differences in mean temperature and highest temperature for all the studied groups. The difference in mean whole portion temperature between the normal cervix and invasive planoepithelial cancer amounted to 1.4 degrees C while in comparison to other lesions it did not exceed 0.5 degree C. Statistical analysis of the averaged profiles of cervical temperatures has also shown significant differences between invasive cancer and the remaining groups--by 1.5 degrees C in average. Strong interrelationships (p < 0.001) were found among the single results of thermography measurements within all the groups. The thermographic profiles of all 14 thermograms of normal portion did not exceed the two standard deviations range of the established standard with the mean temperature of 36.56 degrees +/- 0.56 degree C. CONCLUSIONS: 1. The established thermographic mapping patterns of the normal cervix may form a basis for the future evaluation of the diagnostic application of computer thermography in gynecology. 2. Statistically significant differences were found in thermographic profiles of the portion between the normal cervix and such cervical lesions as endocervical polyp, erosion (PAP II), CIN and invasive cancer. 3. Invasive cervical cancer reveals thermographic pattern of relatively high specificity within the analyzed cervical lesions.

Adult↗

PubMed1998

Mixed dentition analysis for Hong Kong Chinese.

Using simple linear regression analyses, prediction equations for the combined mesiodistal crown diameters of canines and premolars based on lower incisor size were generated from 97 Hong Kong Chinese (51 males and 46 females, average age 12.31 years) out of a sample of 112. The mesiodistal crown diameters of the permanent teeth were measured using calipers and recorded to the nearest 0.01 mm. Significant sex differences were found for the combined diameters of the canine-premolar segments. The coefficients of correlation between combined diameters of canines and premolars and lower incisors ranged from 0.65 to 0.79. Significant sex differences of the regression equations were found and thus four simple linear regression equations were generated. Coefficients for the slope ranged from 0.58 to 0.66, and coefficients for the intercept ranged from 6.66 to 8.82. The R2 values, standard errors of estimate, and absolute mean errors revealed that prediction models for females were less precise than those for males. Probability tables were constructed from the results of the present study. The prediction equations were found to differ from those of Tanaka and Johnston. Accuracy in the mixed dentition analysis for southern Chinese would be improved by applying the prediction equations or probability tables generated from the present study.

Asian People↗

PubMedDate not supplied

[Impact of universal varicella vaccination in Germany: an epidemiological and economic analysis].

Varicella is a highly contagious viral disease which mainly affects young children and usually is perceived as infection with a mild disease course. However, there is increasing evidence indicating that the morbidity and mortality as well as the economic impact associated with varicella are significant. While universal childhood vaccination against varicella is currently not recommended in Germany, the availability of safe and efficacious vaccines offers the opportunity for preventive intervention. Detailed and reliable data on the consequences of varicella and the possible impact of a universal vaccination program are missing to date for Germany. In order to generate this information, we conducted a comprehensive evaluation. The objective was to quantify the medical consequences and the economic impact of varicella on third-party payers and the society by means of a model analysis, and particularly to assess the effects of various universal vaccination strategies. The study confirms that varicella represents a significant health and economic burden in Germany. Following mathematical modelling, universal varicella vaccination for children at the age of 12-18 months could prevent more than 82 % of cases and complications on average per year. Economically, universal vaccination would lead to net cost savings not only for the society but also for the third-party payers. From these findings it can be concluded that universal varicella vaccination is a strategy which should be encouraged, from a medical, epidemiological, but also economic viewpoint.

Chickenpox↗

PubMed1994

Dietary protein alters tubular iron accumulation after partial nephrectomy.

Reactive oxygen species (ROS) have been implicated in progression of disease in the rat remnant kidney (RK) model of chronic renal failure. Substantial amounts of iron accumulate in proximal tubular lysosomes of RK and could damage tubules by ROS generation. The effect of dietary protein intake on ROS, tubular damage and iron accumulation assessed by energy dispersive analysis was determined in RK (5/6 nephrectomy, N = 12) and sham-operated kidneys (SO, N = 10). In RK, mean lysosomal iron concentration, urinary iron and protein excretion and morphological damage were increased and GFR decreased. Dietary protein loading (40% vs. 12%) increased the number of iron-containing lysosomes (P < 0.05) and the mean lysosomal iron (P < 0.02) in proximal tubular cells after four weeks. In RK, high protein diet increased renal weight (P < 0.01), numerical density of iron-containing lysosomes and tubular damage (both P < 0.05). ROS generation, assessed by tissue and plasma malondialdehyde (MDA), was also increased (both P < 0.05). Plasma MDA correlated with tubular iron accumulation (r = 0.75). In RK fed a high protein diet (N = 18) treatment with the iron-chelator desferrioxamine reduced serum iron, urinary volume, and tubular iron accumulation and damage compared to controls (P < 0.01). In summary, in RK dietary protein manipulation altered urinary iron and protein excretion, proximal tubular iron accumulation, renal cortical ROS generation and ultrastructural damage. Desferrioxamine treatment reduced tubular lysosomal iron and ultrastructural damage. These results suggest a role for tubular iron as a determinant of tubular injury associated with dietary protein loading in rats with partial nephrectomy.

Animals↗

PubMed2006

Influence of post-etching cleaning and connecting porcelain on the microtensile bond strength of composite resin to feldspathic porcelain.

STATEMENT OF PROBLEM: There are different methods to fabricate layered feldspathic porcelain restorations, including the refractory die technique and the hot-press technique. Standard adhesive protocol for such restorations requires etching and silanating the fitting surface of the porcelain. Variations in bond strength between porcelain and composite resin might result from the different fabrication methods for porcelain restorations. PURPOSE: The purpose of this study was to determine differences in microtensile bond strength between composite resin (used as a luting agent) and feldspathic porcelain generated from the refractory die technique using 2 different connecting porcelains and the hot-press technique. The effect of post-etching cleaning was also investigated. MATERIAL AND METHODS: Sixteen pairs of ceramic blocks (7 x 8 x 4 mm) were fabricated. Eight pairs were fabricated using feldspathic porcelain (D-B4) on refractory dies. For 4 pairs, the refractory dies were coated with a paste (Ducera Lay Connector Paste; group CON) as a connecting porcelain, and the other 4 pairs were coated with a clear translucent porcelain (CL-O; group CLO). Another 8 block pairs were fabricated using the hot-press technique (Authentic porcelain SL B00+; groups AUTH and AUTH-N). Surface conditioning of the ceramic blocks included airborne-particle abrasion followed by hydrofluoric acid etching (all groups), and post-etching cleaning with a brush/H3PO4 and ultrasonic bath immersion (cleaning not applied to group AUTH-N). All specimens were then silanated/heat dried, and blocks of the same porcelain were bonded to each other using an adhesive resin (Optibond FL) and a light-polymerizing composite resin (Z100). Specimens were stored in water for 24 hours. A nontrimming microtensile bond strength test was applied. Ten beams (0.9 x 0.9 x 8 mm) from each pair of blocks were selected for testing. Bond strength data (MPa) were analyzed with a Kruskal-Wallis test, and post hoc comparison was done using the Mann-Whitney U test (alpha = .05). Additional specimens (1 block per group) were also evaluated for the effect of conditioning steps and mode of fracture using optical microscopy and scanning electron microscopy (SEM) analysis. RESULTS: The mean microtensile bond strengths of CLO and AUTH groups were not significantly different from one another at 46.3 and 49.7 MPa, respectively. For both CON and AUTH-N groups, the mean bond strengths at 37.9 MPa and 24.1 MPa, respectively, were significantly different (P < .05) from the other 3 groups. Optical microscopy revealed a significant amount of white residue for all groups as a result of hydrofluoric etching. Cleaning with a microbrush and 37.5% phosphoric acid for 1 minute resulted in the removal of the crystalline debris. The SEM analysis of specimens cleaned by phosphoric acid brushing alone revealed microscopic deposits still contaminating the etched surface; those were efficiently removed after ultrasonic cleaning. The SEM analysis of fractured beams demonstrated a trend for more mixed-type failure in CON and AUTH-N specimens involving both the composite resin and the surface of the porcelain, whereas CLO and AUTH fractured surfaces were primarily confined to the composite resin. CONCLUSIONS: Increased resin bond strength to refractory-generated porcelain is obtained with CLO as the connecting porcelain compared to the CON paste. The AUTH porcelain exhibited the highest mean bond strength, but omission of post-etching cleaning resulted in the lowest bond strength.

Acid Etching, Dental↗

PubMed1987

Evaluation of in vivo drug release by numerical deconvolution using oral solution data as weighting function.

Determination of in vivo drug release using compartmental model analysis is hampered by problems such as flip-flop phenomena and vanishing exponential terms. The usefulness of numerical deconvolution to estimate in vivo drug release was evaluated in this study by means of simulated data comparing solid dosage forms with a solution as a reference standard. Concentration-time data were generated using the standard linear two-compartment body model with various first-order release and absorption rate constants. Random errors of 5 and 10% were added to data sets for further analysis. The results of the study using error-free data afforded excellent agreement with the theoretical values except in one case where the release rate constant was overestimated by 6%. When random error was added to the data, the resulting in vivo release profile showed considerable fluctuation and no single rate constant could be assigned. However, further analysis showed that the method does not create additional error during the calculating process, as previously suggested, but merely reflects the inherent error added to the raw data. If the raw data are poor, no useful information can be obtained without using an arbitrary technique such as smoothing or fitting. In this regard, the time course of drug release obtained after numerical deconvolution merits investigation.

Absorption↗

PubMed2006

Genetic studies in variegate porphyria in Spain. Identification of gene mutations and family study for carrier detection.

BACKGROUND: First, to establish the mutations of the protoporphyrinogen-oxidase (PPOX) gene in four Spanish patients with variegate porphyria (VP). Second, study of carrier status detection in the families, including a four-generation Balearic family. Third, evaluation of the results of carrier detection screening methods. DESIGN: Blood samples of four patients and of 139 members belonging to four families, including four generations of a Balearic family were processed for mutation analysis of the 13 exons of PPOX gene. Biochemical studies were performed together (blood and faecal porphyrin analysis) and plasma fluorescence scanning for 626 nm peak emission detection. A questionnaire regarding clinical manifestations was submitted to all family members studied. RESULTS: Single strand conformational analysis (SSCP) of DNA allowed the detection of the following mutations: W224R, 746delT: exon 7, 1077-1082insC: exon 10, and IVS6+2T-->A. Mutation was present in 19 of the 139 members of the families studied. Clinical manifestations or biochemical alterations were checked in the carriers detected and found as not relevant or not present. Only 11 members of the 19 mutation-bearing individuals showed plasma fluorescence PV peak positivity. CONCLUSION: Demonstration of gene mutation is the most reliable means of detecting carriers in studies of variegate porphyria families. DNA analysis is the most sensitive carrier detection method and also allows transmission behaviour of the genetic defect to be established in successive generations of the affected families.

Adult↗

PubMed2005

Evaluation of sieving polymers for fast, reproducible electrophoretic analysis of short tandem repeats (STR) in capillaries.

Efficient capillary electrophoretic STR analysis requires rapid, reproducible and robust separation of DNA fragments with reasonable capillary longevity--this is currently accomplished using proprietary commercial polymeric sieving matrices specifically developed for this separation. These matrices, while effective, are costly and do not provide adequate resolution of STR DNA fragments in capillaries with shorter effective separation lengths, increasing the time required to accomplish the separation and minimizing the potential extrapolation to other miniaturized platforms. As the forensic community looks toward next generation microchip technology as a means of processing casework more rapidly, new sieving polymers need to be evaluated for utilization in this platform. The research presented here describes the assessment of commercially-available polymeric sieving matrices for STR analysis, with consideration given to feasibility of incorporation into a microdevice. Polymer composition, molecular weight, and concentration were evaluated, along with an assessment of the effects of buffer composition, separation temperature, and capillary length. These variables were evaluated individually or collectively on the ability to resolve STR DNA fragments and the reproducibility of the separations and the results compared to a proprietary commercial product. A 600,000 Da MW poly(ethylene oxide) (PEO) solution at a 3% (w/v) concentration was determined to be the most suitable matrix for these separations. This polymer, in coated capillaries, provided highly robust and reproducible separations, with near baseline resolution of fragments having single base differences. Reductions in the temperature of the separation, from 60 degrees C to 40 degrees C, and the urea concentration of the buffer, from 7 M to 3.5 M, provided increased longevity of the PEO polymer for repeated separations. Comparison of this polymer with currently specified commercial products used for STR analysis showed that the optimized PEO matrix provided superior separations under all conditions tested. In addition, PEO could be utilized in shorter capillary systems, with a concurrent decrease in analysis time, highlighting its potential for use in shortened capillary or microdevice systems.

Buffers↗