Determination Of Rapid Changes Research Articles

Rapid Determination of Changes in Material Properties of Water Turbines Blades

The changes in the material properties of water turbine blades are characterized an undesirable process, which could lead to the end of usable life or to the emergency conditions of this turbine. For this reason, it is important to determine of any material quality changes and continuously monitor them. Considering that, these essential parameters are showing the ability of material to resist the operational stress. It is necessary to choose rapid methods of the material testing which are without preparation of the samples (it is inadmissible to the functional blades) able to immediately monitor the state of the materials by non-destructive methods. Due to mechanical stress and operational wear, the losses and damage occur in the water turbine blades, as the result, it leads to the deformation changes. This article is focused on the methodology of determination mechanical properties of corrosion-resistant steel, which is used on a large scale for the production of hydraulic elements and especially blades of water turbines.

Changes in Serum B-Cell Maturation Antigen Levels Rapidly Indicate Changes in Clinical Status Among Multiple Myeloma Patients Undergoing New Treatments

Introduction : B-cell maturation antigen (BCMA) is a protein that is expressed on the plasma cells from patients (pts) with multiple myeloma (MM). Our group has previously shown that MM pts have higher levels of serum (s) BCMA than healthy subjects and that sBCMA levels can be used to monitor the disease course of MM pts. Notably, we have shown that the half-life of soluble BCMA is only 24-36 hours which is much shorter than sM-protein, and its levels are independent of renal function. With the expanding therapeutic options for the treatment (Tx) of MM, there is a need for more rapid and accurate ways to assess the efficacy of new therapies. To this end, we compared changes in levels of sBCMA with sM-protein among MM patients undergoing new treatments.Methods : Serum was obtained at least weekly during each pt's first cycle of a new therapy (C1) and the first day of their second cycle (C2D1) and at least monthly thereafter from all MM pts receiving a new Tx regimen (n=83) at a single clinic from March 2015 to July 2017. sM-protein levels were measured, and sBCMA levels were determined using an enzyme-linked immunosorbent assay (R&D Systems; Minneapolis, MN). Percentage changes in sBCMA and sM-protein throughout Tx were determined relative to levels measured at their start of treatment (C1D1). Kaplan-Meier analysis was used to assess differences in time on therapy (TOT) based on the percentage changes in sBCMA levels at cycle 1 day 8 (C1D8) and day 15 (C1D15) of the pt's new Tx. All patient samples were obtained following proper informed consent in accordance with the Declaration of Helsinki.Results : Forty-nine MM pts (IgG [n=37], IgA [n=12]) receiving 83 Tx regimens were analyzed. Regimens that resulted in a > 25% increase in sBCMA by C1D8 (n=10) had a shorter median TOT than all other regimens (n=71; median TOT: 1.73 months vs. 5.76 months; P=.0037). Regimens that showed a > 25% decrease in sBCMA levels on C1D8 (n=27) had a longer TOT (median TOT: 6.91 months) when compared with all other regimens (median TOT: 2.89 months). In contrast, sM-protein levels did not show > 25% changes at these early time points.For those patients who achieved at least a minimal response (MR) using IMWG criteria (n=30), the time to achieve at least a 25% decrease in sBCMA was much shorter (median 7 days) than the time for sM-protein (median 21 days; P=.0004). For those that progressed during the first cycle (n=5), the time to achieve at least a 25% increase in sBCMA was similarly much shorter (median 7 days) than the time for sM-protein (median 21 days).Because the half-life of IgG is long (approximately 3-4 weeks), we studied the 64 regimens among the 37 pts with IgG MM. Twenty-four (38%) achieved at least an MR. Among these pts, sBCMA levels reduced by an average of 31% on C1D8, whereas sM-protein decreased by an average of only 7.6%.The regimens that resulted in a > 25% decrease on C1D8 (n=23) had a longer TOT than regimens that did not reach this reduction (n=41; median TOT: 7.8 months vs. 2.8 months, P=.023). Those regimens with a confirmed > 25% increase in sBCMA levels (n=6) at C1D15 had a shorter TOT than those with a confirmed > 25% decrease in sBCMA levels (n=22) at C1D15 (median 0.9 months vs. 6.9 months, P <.0001), and had a shorter TOT than all other Tx regimens (n=75; median 0.9 months vs. 5.8 months, P <.0001).There were six regimens for which pts did not achieve a response during the first cycle but did so during subsequent cycles. At C1D8, sBCMA levels decreased > 25% in four pts and 24% in another pt. During the second week of therapy, sBCMA levels continued to decrease in these five pts. In contrast, sM-protein did not show a response (> 25% decrease) in any of these regimens during C1 and decreased by an average of only 9.7% and 13.3% on days 8 and 15, respectively.Conclusions: We have shown that relative changes in sBCMA levels from baseline can much more rapidly determine changes in clinical status than the standard sM-protein biomarker among MM pts starting new treatments. By C1D8, sBCMA establishes changes in clinical status whereas sM-protein takes much longer to show the effect of treatment on response status. In addition, a > 25% increase or decrease in sBCMA levels at C1D8 indicates a much shorter or longer TOT, respectively for these pts. Thus, relative changes in sBCMA levels among MM pts on new therapies allows more rapid determination of changes in their clinical status, and these early changes predict the length of time on those treatments. DisclosuresBerenson:OncoTracker, Inc.: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Incyte: Consultancy, Research Funding.

Rapid Oligonucleotide Drug Impurity Determination by Direct Spectral Comparison of Ion Pair-Reversed Phase HPLC ESI MS Data.

Quantitative Ion-Pair (IP)-HPLC MS methods are employed to determine the complex impurity profiles of oligonucleotide therapeutics. While impurities that co-elute with the main product are routinely monitored, the large number of early and late eluting impurities makes their individual measurements tedious and time-consuming. An improved method is needed for routine analyses. A Combined Ranking (CR) index is developed to provide a composite value for both qualitative and quantitative impurity changes. Positive and Negative Impurity Change (PIC/NIC) indices are developed to determine the degree and direction of change. Optimized experimental conditions are determined for the characterization of trace levels of impurities. Replicate analysis, blank subtraction, and signal processing approaches are used to enhance the S/N. Dot-product and Euclidean distance equations monitor spectral changes. Spiking experiments with individual and complex impurity mixtures show the method can distinguish among samples differing in impurity content by 0.2% wt. The method has been applied to monitor changes in impurity profile among different batches of the same oligonucleotide and changes in the same batch over time (stability analysis). The method permits rapid determination of changes in the types and amounts (increases and decreases) of impurities present. A novel approach for the rapid determination of changes in the impurity profile of oligonucleotide therapeutics has been developed. The straightforward data treatment and the speed and simplicity of the approach make the method easy to implement and use. Possible quality control applications include drug substance and drug product stability studies, and the assessment of batch-to-batch variability.

Rapid monitoring of sulfur mustard degradation in solution by headspace solid‐phase microextraction sampling and gas chromatography mass spectrometry

A method using headspace solid-phase microextraction (HS-SPME) followed by gas chromatography/mass spectrometry (GC/MS) analysis has been developed to gain insight into the degradation of the chemical warfare agent sulfur mustard in solution. Specifically, the described approach simplifies the sample preparation for GC/MS analysis to provide a rapid determination of changes in sulfur mustard abundance. These results were found to be consistent with those obtained using liquid-liquid extraction (LLE) GC/MS. The utility of the described approach was further demonstrated by the investigation of the degradation process in a complex matrix with surfactant added to assist solvation of sulfur mustard. A more rapid reduction in sulfur mustard abundance was observed using the HS-SPME approach with surfactant present and was similar to results from LLE experiments. Significantly, this study demonstrates that HS-SPME can simplify the sample preparation for GC/MS analysis to monitor changes in sulfur mustard abundance in solution more rapidly, and with less solvent and reagent usage than LLE.

Identification of HLA-DRB1-bound self-peptides following measles virus infection

We developed a B-lymphocyte cell line derived from a measles seropositive individual who was homozygous for the HLA-DRB1*0301 allele. Peptides associated with the HLA-DRB1*0301 protein were purified from this lymphoblastoid cell line after infection with the Attenuvax™ measles vaccine virus (Merck Research Laboratories, West Point, PA) and with “sham” infection. More than 40 peptide sequences were obtained by nano-scale reversed phase-high performance liquid chromatography coupled to tandem mass spectrometry (nano-LC/MS/MS). These peptides originated from 21 different source proteins—the majority from membrane-bound proteins. Most of the peptides (>73%) bound to HLA-DRB1*0301 appeared to be in lower abundance on measles-infected cells compared to the “sham-infected” cells. However, 26% of the identified peptides seem to have increased expression after measles infection. Measles vaccine virus infection did not change the level of HLA-DR expression. We demonstrate the power of nano-LC/MS/MS in the rapid determination of changes in the spectrum and expression of HLA-DRB1*0301-bound peptides after infection with measles virus. This provides further knowledge of the changes in peptide expression after viral infection and provides a powerful tool for identifying HLA-presented host and viral epitopes in the context of class II HLA molecules.

Changes in portal hemodynamics and acute rejection in the first 2 weeks after orthotopic liver transplantation. A prospective Doppler ultrasound study.

To analyze changes in Doppler ultrasound variables of the portal vein in relation to liver biopsy findings, the authors performed a prospective study of 316 Doppler ultrasound examinations in the first 2 weeks after orthotopic liver transplantation on 23 patients. Recordings were obtained daily from the portal vein (diameter, maximum velocity, and flow). Correlations were explored between the Doppler ultrasound findings and histologic data. The chi-square test was used to analyze differences in Doppler ultrasound variables in patients with and without acute rejection. In our series of 23 patients, acute rejection was diagnosed by liver biopsy in nine of them (39%). Changes in portal vein diameter, maximum velocity, and flow did not correlate consistently with liver biopsy findings, due to a multifactorial origin. Changes in portal hemodynamics were observed in patients with hepatic artery thrombosis, portal vein stenosis, acute rejection, and sepsis. Although routine screening using Doppler ultrasound proved to be useful for the determination of rapid changes in portal hemodynamics within a short time, serial Doppler ultrasound examinations were not helpful in predicting acute rejection.

Flow‐Cytometric Determination of the Respiratory Activity in Growing Saccharomyces cerevisiae Populations

AbstractFlow cytometry allows one to measure relevant physical or chemical properties on a single cell, yielding the distribution of these properties in the cell population. Typically, flow cytometry has been used to determine DNA or protein distributions, but it could be extended to the determination of other relevant parameters, such as intracellular pH, membrane potential, intracellular Ca2+ concentration, mitochondrial activity, etc. In the present work, we used flow cytometry to determine the respiratory activity in intact Saccharomyces cerevisiae cells after staining with the cationic lipophilic dye rhodamine 123 (Rhl23). We found a good correlation between the Rh123 fluorescence distribution in yeast populations and the degree of respiratory activity, which can be varied by changing the carbon source used for yeast growth. In addition, we developed a vital staining procedure which allows one to measure fast changes in the respiratory activity. We used this technique to follow the kinetics of glucose repression and to measure the apparent Km for the substrate. Our results demonstrate that flow cytometry is a fast and very sensitive method to evaluate the respiratory activity in yeast cells and is also suitable for the determination of rapid changes in yeast metabolism. Biotech‐nological implications of this study are also discussed.

Hydraulische Leitfähigkeit von Valonia utricularis / Hydraulic Conductivity of Valonia utricularis

A method is described for the simultaneous determination of rapid changes of the cell turgor pressure (hydrostatic pressure) in algal cells (cell size must be at least 3 mm in diameter), and of the net volume flow across the cell membrane arising after a change of the cell turgor pressure or of the osmotic pressure in the outside medium. On the basis of the equations of irreversible thermodynamics it is possible to calculate the hydraulic conductivity of the cell membrane from these measurements, as it is theoretically shown. The hydraulic conductivities of the marine alga Valonia utricularis determined in two independent ways (by osmotic and hydrostatic experiments) are equal. For exosmosis, Lpex (hydrostatic) and Lpex (osmotic) amounted to (9,6 ± 1,0) ·10-7 and (9,8 ± 1,9) · 10-7 respectively cm · sec-1 · atm-1, and for endomosis, Lpen (hydrostatic) was (9,4 ± 1,1) ·10-7 cm · sec-1 · atm-1. A polarity in the water movement across the cell membranes as discussed in the literature could not be found for Valonia utricularis.

The Use Of Pulsed Applied Voltage in the Derivation of Corrosion Rates From Polarisation Resistance Measurement

Abstract An experimental technique has been developed for the rapid determination of changes in corrosion rates using the well established Stern–Geary equation. The value of the technique was demonstrated for the corrosion rates of aluminium brass in seawater and in seawater containing 0·01% sodium dimethyl dithiocarbamate for which the corrosion characteristics had been established previously. An instrument based on these principles could be developed for a variety of corrosion measurement application.