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At least 235 records · Page 13Linked to original sources
PubMed2006

New method to measure packing densities of self-assembled thiolipid monolayers.

For a monolayer of 2,3-di-phytanyl-sn-glycerol-1-tetraethylene glycol-D,L-a-lipoic acid ester lipid (DPTL) self-assembled (SAM) at a gold electrode surface we propose a new method to determine the charge number per adsorbed molecule and the packing density (area per molecule) in the monolayer. The method relies on chronocoulometry to measure the charge density at the SAM covered gold electrode surface. Two series of measurements have to be performed. In the first series, charge densities are measured for a monolayer transferred from the air-solution to the metal-solution interface using the Langmuir-Blodgett (LB) technique. This series of measurements allows one to determine charge numbers per adsorbed DPTL molecule. The second series is performed using a gold electrode covered with a self-assembled monolayer. The charge densities obtained in this series are then used to calculate the packing density with the help of charge numbers per adsorbed DPTL determined in the first series. The area per adsorbed molecule determined by the new method was compared to the area per molecule determined by the popular reductive desorption method. The molecular area determined with the new method is about 20% larger than the area calculated from the van der Waals model, which is a physically reasonable result. In contrast, the popular reductive desorption method gives an area per molecule 20% lower than the minimum estimated based on a van der Waals model. This is a physically unreasonable result. It is also shown that the charge numbers per adsorbed molecule depend on the electrode potential and may assume values smaller than the number of electrons participating in the reductive desorption step. An explanation of the origin of the "partial charge numbers" is provided. We recommend the new method be used in future studies of thiol adsorption at metal surfaces.

Journal Article↗
PubMed1983

Schistosoma mansoni: new method for recording motor activity in vitro.

A new method for recording the motility of Schistosoma mansoni in vitro is described. Spontaneous activity of the worm shows contraction similar to peristalsis. The worm responded to electrical stimulation with an immediate contraction that was voltage dependent. Oxamniquine produced an increase in the tonus and spontaneous activity of the worm. This method provides a new experimental model for the study of drugs that interfere with Schistosoma mansoni motility.

Animals↗
PubMed1981

A new method for long-term monitoring of the ballistocardiogram, heart rate, and respiration.

The principle of the static charge-sensitive-bed (SCSB) method is described. The method is simple and inexpensive. From the SCSB recording the ballistocardiogram (BCG) and respiratory movement can be simultaneously recorded by selective filtering of the original signal. The SCSB recording thus enables continuous long-term monitoring of the BCG, heart rate, respiratory rate, respiratory amplitude, and body movements. There are no electrodes or cables connected to the subject. The SCSB-BCG signal was studied by comparing the SCSB method with the conventional ultralow-frequency (ULF) acceleration BCG. The wave forms at rest and the amplitude responses to physical exercise were studied by both methods. Multiple recordings of the BCG, heart rate, respiratory movement, respiratory rate, and body movements after exercise and during sleep using the SCSB method are presented. The SCSB method opens new approaches to long-term studies of the regulation of myocardial performance, heart rate, and respiration. Applications of the SCSB method for clinical sleep studies, patient monitoring and cardiovascular screening examinations are discussed.

Adult↗
PubMed2005

[Capsule endoscopy--a new method for the diagnosis of diseases of the small intestine].

BACKGROUND: Diseases of the small intestine are rare and often difficult to diagnose because of a lack of sensitive methods. A new technique called wireless capsule endoscopy has recently been developed; it allows visualisation of the entire small intestinal surface. MATERIAL AND METHODS: The patient swallows a capsule containing a small digital camera, a battery and a radio transmitter. The capsule takes 2 pictures per second during its passage through the intestines; pictures are transferred by radio signals that are detected by sensors on the abdominal skin, stored on a data recorder and later analysed on a PC. RESULTS: By the end of November 2003 we had performed 80 capsule endoscopies in 69 patients. All patients were referred because of suspected small bowel disease and had been through an extensive diagnostic workup before capsule endoscopy was performed. Most of them were referred because of obscure gastrointestinal bleeding or iron deficiency anaemia. Small bowel pathology was found in one third of the patients. INTERPRETATION: Capsule endoscopy seems to be a major improvement in the diagnosis of small intestinal diseases. It is a non-invasive and painless procedure.

Adult↗
PubMed1978

[New method of estimating x-ray magnification on angiographic volume determinations (author's transl)].

1. The necessity of a precise determination of the magnification factor for angiographic volume determinations is described. Each error of the linear magnification factor influences in its third power the volume calculation. 2. For the magnification of linear cineangiographic magnification a method is used in which the tip of the catheter is filmed in two positions. The distance approximately resembles a normal ventricular diameter. The relationship of virtuel shifting of the catheter tip versus real shifting of the patient is the magnification factor. 3. For the practicable handling of this method a new developed mechanical device is described which allows the performance of the calibration procedure with an adequate high precision. 4. The method is simple and can be done within a short period of time.

Angiography↗
PubMed2003

[A new method of complete peripheral margin assessment in breast conservative surgery using an adjustable polygonal prism mould].

UNLABELLED: Conventional margin evaluation for breast conservative surgery is usually based on the sections taken perpendicular to the inked margins and has difficulty in completeness. We have developed a new method using an adjustable mould during fixation so that the three-dimensional specimen is fixed in the shape of polygonal prism. The new method enables us to assess peripheral margins completely by examining the inner surfaces of the marginal slices cut parallel to the flat peripheral margins of the specimen. DESIGN: We have applied the new method to 59 invasive carcinomas and 10 noninvasive carcinomas of the breast, which were judged to be negative for residual tumor by conventional inked margin on the section cut through the center of the tumor. RESULTS: The new method detected 13(22.0%) and 3(30.0%) cases with positive margins in 59 invasive carcinomas and 10 noninvasive carcinomas of the breast, respectively. Nine of 13(69.2%) positive margins in invasive carcinomas were due to the intraductal components of the carcinomas. CONCLUSION: The polygon method is superior to the conventional inked margin method in sensitivity. Furthermore, it covered all the peripheral margins and pinpointed the positive sites.

Breast↗
PubMed1986

A new method for assessing the % of spirochaetes in subgingival plaque.

A new method for counting the numbers of spirochaetes in subgingival plaque is described. The technique involves the combined use of a negative stained preparation, dark field microscopy, and an image analysing system. Advantages of the method include: smears need not be made until 2 days after sampling, and can be examined microscopically for up to 1 year after preparation; reproducibility of counts are more than 90% and the data can be computerised. The new method should prove useful in the routine assessment of subgingival plaque from patients with various forms of periodontitis, and in epidemiological surveys.

Aniline Compounds↗
PubMed1995

[A new method for evaluating acute toxicity intragastrically for classification of chemical substances].

The authors reviewed and presented a critical analysis of the literature on defining acute toxicity of chemicals after intragastrical administration by means of traditional methods and new ones such as fixed procedure, up-down, acute-toxic-classification. Rules and conditions for the evaluation of acute toxicity by means of these methods were presented as well as the way of defining a median, lethal dose administrated intragastrically for the purpose of chemical classification.

Administration, Oral↗
PubMed1976

[Isolation and function of platelets. I. Platelet rich plasma. Comparison between 2 methods: gel filtration and albumin density gradient centrifugation. II. A new method using total blood: metrizamide gradient centrifugation].

Human platelets separated from platelet rich plasma (PRP) by two different methods: gel filtraton and centrifugation on albumin gradient have been compared for yield, cellular and protein contamination, ultra-structure, platelet populations, shape change, aggregability and functional preservation. A new method for the separation of platelets from total blood on metrizamide gradients has been established. This technique is rapid and easy; it avoids the initial centrifugation of the PRP where about 30% of the platelets are lost and needs of blood 5 to 10 ml of blood.

Blood Platelets↗
PubMed2005

A new method for estimating the effectiveness of emergency contraception that accounts for variation in timing of ovulation and previous cycle length.

OBJECTIVE: To develop a new method for estimating the effectiveness of emergency contraception (EC) by using information about previous menstrual cycle length, accounting for the variation in the day of ovulation within the menstrual cycle, and comparing the validity of the new and previous methods. METHOD(S): Secondary analysis of a data set with a biological marker of ovulation and its distribution in the cycle. Based on a sample of cycles with known length and a known biological marker of ovulation, we simulated trials of predetermined EC effectiveness and then calculated estimates of EC effectiveness based on old and new methods. RESULT(S): Under some conditions, all methods produced biased estimates of effectiveness with simulated trials, especially when the actual effectiveness was low. The systematic bias was minimized with the new method. The new method was robust with regard to the distribution of the day of intercourse in women presenting for EC. CONCLUSION(S): Future studies of EC effectiveness should consider both the uncertainty in predicting the day of ovulation and previous cycle length. Our estimates of daily fecundity should be replicated with other data sets.

Contraception, Postcoital↗
PubMed2004

A new method to denude the endothelium without damage to media: structural, functional, and biomechanical validation.

The intimial thickening that occurs in human and animal atherogenesis can be induced by mechanical injury to the endothelium. The objective of the present study was to develop a new method to induce arterial endothelial injury without damage to the media for future investigations of mechanisms of intimal thickening and atherogenesis. A specifically designed catheter was inserted into the common femoral artery of Wistar rats (n = 9) through an arteriotomic mouth. After application of Tyrode solution containing 0.14 M KCl on the surface of the vessel, the vessel contracted onto the catheter. The catheter was then moved back and forth to scrape away the endothelium. The left common femoral artery of the same rat was subjected to the standard balloon injury model. The two models were evaluated structurally, functionally, and biomechanically. Structurally, we verified that both techniques remove the endothelium, but the balloon method damages the media. Functionally, we examined the contractile response of the artery to [K+] and norepinephrine 2 days after the denudation. We found that the right femoral artery underwent contraction in response to [K+], whereas the left artery did not. Furthermore, neither artery responded to norepinephrine. Biomechanically, we measured the pressure-diameter relationship and the zero-stress state of the vessel and computed the stress-strain relation. The circumferential stretch ratios at 120 mmHg were 1.38 +/- 0.08 for the control, 1.41 +/- 0.08 (P > 0.05) for the new method, and 1.56 +/- 0.09 for the balloon injury (P < 0.05). The opening angles at the zero-stress state were 113 +/- 21 degrees for the control, 102 +/- 18 degrees for the new method (P > 0.05), and 8 +/- 13 degrees for the balloon injury (P < 0.001). In conclusion, the new method removes the endothelium while maintaining the structure, contractile function, and biomechanical properties of the vessel.

Animals↗
PubMed1978

A new method for the purification of 30S ribosomal proteins from Escherichia coli using nondenaturing conditions.

A new method for the purification of Escherichia coli (A19) 30S ribosomal proteins has been developed that avoids the use of denaturing conditions such as urea, acetic acid, and lyophilization. In this way the majority of the proteins from the small ribosomal subunit can be obtained in 5--100 mg quantities and at greater than or equal to 90% purity. This has been achieved by the initial "splitting" of the proteins into two main groups with LiCl followed by fractionating on ion-exchange and gel-filtration columns, in the absence of urea and in the presence of salt. The proteins prepared by this nondenaturing procedure were soluble at high ionic strength and less soluble, being aggregated, at low salt concentrations. This behavior was exactly the opposite of that exhibited by proteins prepared with methods using denaturing conditions. These new methods have enabled additional ribosomal RNA-binding proteins to be found and potential protein-proteins complexes to be isolated. Preliminary evidence that these proteins may retain a more native structure is presented.

Escherichia coli↗
PubMed1992

Development and application of a new method to extract bacterial DNA from soil based on separation of bacteria from soil with cation-exchange resin.

A new method for the extraction of bacterial DNA from soil has been developed. Soil samples of 50 g were dispersed, and bacteria were released by use of a cation-exchange resin; subsequently, bacteria were separated from soil particles by low-speed centrifugation and lysed with lysozyme and ionic detergent, and the DNA was then purified by CsCl-ethidium bromide equilibrium density centrifugation. The extracted DNA was of high molecular weight and sufficiently pure for restriction enzyme digestion, DNA-DNA hybridization, and amplification by the polymerase chain reaction. The advantages of the new method are that the separation of bacteria from soil is considerably faster than by repeated blending, more samples can be handled, and furthermore no aerosols are formed during separation. Also, we investigated whether the CsCl-ethidium bromide equilibrium density centrifugation could be replaced by purification using Gene-Clean. However, this method produced DNAs which were insufficiently pure for several types of analysis. The new method was used to study survival of a 2,4-dichlorophenoxyacetic acid (2,4-D)-degrading Pseudomonas cepacia DBO1 (pRO101) in unamended soil and in soil amended with 2,4-D. We found that the degrading strain, irrespective of inoculation level, was able to grow to the same high numbers in soil amended with 2,4-D, while the strain in nonamended soil were maintained at the inoculation level. Detection based on DNA extraction and subsequent dot blot DNA-DNA hybridization was in accordance with detection by plating on selective medium.

Journal Article↗
PubMed1993

[A new method of isolation and purification of SsoII restriction endonuclease].

A new method for isolation and purification of restriction endonuclease SsoII which results in a homogeneous preparation suitable for all types of fine physico-chemical assays has been elaborated. The procedure includes four chromatographic steps: fractionation on butyl-Toyopearl, combined chromatography on SP-Toyopearl and phosphocellulose PII, and chromatography on DEAE-Toyopearl and on QAE-Toyopearl. The use of fast flow sorbents (Toyopearl) makes it possible to reduce the time needed for the separation of proteins and to optimize the fractionation conditions, thus avoiding the dialysis between the chromatographic steps which significantly decreased the enzyme activity yields in previous purification schemes. The isolation of restriction endonuclease SsoII by the new method usually takes four days.

Chromatography, Ion Exchange↗
PubMed1993

A new method of total reconstruction of the auricle for microtia.

This new method for total reconstruction of the auricle is a two-stage operation in which the first stage involves fabrication and grafting of a three-dimensional costal cartilage framework and the second stage is the ear elevation operation. The three-dimensional frame was designed with emphasis on the fabrication of the helical crus, intertragic notch, and antitragus and by extending the crus helicis and fixing it to the undersurface of the base frame. The reconstructed auricle will have four different floors: the cymba and cavum conchae are the bottom (fourth) level, the crus helicis is the third level, the fossa triangularis and the scapha are the second level, and the helix, anthelix, tragus, and antitragus are the top level. The skin incision was made in a W-shaped fashion to create skin flaps with ample surface area to cover the three-dimensional frame without skin grafting. Furthermore, the semilunar costal cartilage was utilized for ear elevation. Thus this new method for total reconstruction of the auricle eliminates the major problems encountered with the conventional method.

Adolescent↗
PubMed1990

New method to determine oxygen cost for contractility.

We developed a new method to determine the oxygen cost for myocardial contractility and applied it to epinephrine in the excised cross-circulated dog heart. We utilized the relation between myocardial oxygen consumption (VO2) and the systolic pressure-volume area (PVA) which represents the total mechanical energy generated by contraction. We first obtained a reference VO2-PVA relation in a baseline contractile state. Then, the end-diastolic and stroke volumes were fixed constant and a global index of ventricular contractility, Emax, was enhanced by infusing epinephrine. The VO2-PVA data point was shifted linearly right-upward with the increases in Emax. From the slopes of both the reference VO2-PVA relation line and the regression line of VO2 on PVA during the gradually increased Emax, we calculated the oxygen cost for contractility, i.e., the ratio of the elevation of the VO2-PVA relation to enhanced Emax in each heart. The ratio was 0.00095 +/- 0.00013 ml O2.ml.mmHg-1.beat-1.100 g LV-2. The result indicates that the oxygen cost for contractility can be reliably and efficiently determined by this new method.

Animals↗
PubMedDate not supplied

A new method of predicting US and state-level cancer mortality counts for the current calendar year.

Every January for more than 40 years, the American Cancer Society (ACS) has estimated the total number of cancer deaths that are expected to occur in the United States and individual states in the upcoming year. In a collaborative effort to improve the accuracy of the predictions, investigators from the National Cancer Institute and the ACS have developed and tested a new prediction method. The new method was used to create the mortality predictions for the first time in Cancer Statistics, 2004 and Cancer Facts & Figures 2004. The authors present a conceptual overview of the previous ACS method and the new state-space method (SSM), and they review the results of rigorous testing to determine which method provides more accurate predictions of the observed number of cancer deaths from the years 1997 to 1999. The accuracy of the methods was compared using squared deviations (the square of the predicted minus observed values) for each of the cancer sites for which predictions are published as well as for all cancer sites combined. At the national level, the squared deviations were not consistently lower for every cancer site for either method, but the average squared deviations (averaged across cancer sites, years, and sex) was substantially lower for the SSM than for the ACS method. During the period 1997 to 1999, the ACS estimates of deaths were usually greater than the observed numbers for all cancer sites combined and for several major individual cancer sites, probably because the ACS method was less sensitive to recent changes in cancer mortality rates (and associated counts) that occurred for several major cancer sites in the early and mid 1990s. The improved accuracy of the new method was particularly evident for prostate cancer, for which mortality rates changed dramatically in the late 1980s and early 1990s. At the state level, the accuracy of the two methods was comparable. Based on these results, the ACS has elected to use the new method for the annual prediction of the number of cancer deaths at the national and state levels.

Cause of Death↗
PubMed2005

A new method for estimating joint parameters from motion data.

Joint centers and axes of rotation (joint parameters) are central to all branches of movement analysis. In gait analysis, the standard protocol used to determine hip and knee joint parameters is prone to errors arising from palpation, anthropometric regression equations, and misplaced alignment devices. Several alternative methods have been proposed, but to date none have been shown to be accurate and reliable enough for use in the clinical setting. This article describes a new method for joint parameter estimation. The new method can be summarized as follows: (i) the motions of two adjacent segments spanning a single joint are tracked, (ii) the axis of rotation between every pair of observed segment configurations is computed, (iii) the most likely intersection of all axes (effective joint center) and most likely orientation of the axes (effective joint axis) is found. Initial validation of the method was conducted on a hinged mechanical analog and a single healthy adult subject. For the analog, the center was found to be within 3.8 mm of the geometric center and 2.0 degrees of the geometric axis (standard deviation). For the adult subject, hip centers varied on the order of 1-3 mm, knee centers by 3-9 mm, and knee axes by 2.0 degrees. The results suggest that the new method is an objective, precise, and practical alternative to the standard clinical approach.

Adult↗