Use of a Lyophilized Reference Plasma to Compare Coagulation Test Procedures

1975 ◽  
Vol 34 (02) ◽  
pp. 426-444 ◽  
Author(s):  
J Kahan ◽  
I Nohén

SummaryIn 4 collaborative trials, involving a varying number of hospital laboratories in the Stockholm area, the coagulation activity of different test materials was estimated with the one-stage prothrombin tests routinely used in the laboratories, viz. Normotest, Simplastin-A and Thrombotest. The test materials included different batches of a lyophilized reference plasma, deep-frozen specimens of diluted and undiluted normal plasmas, and fresh and deep-frozen specimens from patients on long-term oral anticoagulant therapy.Although a close relationship was found between different methods, Simplastin-A gave consistently lower values than Normotest, the difference being proportional to the estimated activity. The discrepancy was of about the same magnitude on all the test materials, and was probably due to a divergence between the manufacturers’ procedures used to set “normal percentage activity”, as well as to a varying ratio of measured activity to plasma concentration. The extent of discrepancy may vary with the batch-to-batch variation of thromboplastin reagents.The close agreement between results obtained on different test materials suggests that the investigated reference plasma could be used to calibrate the examined thromboplastin reagents, and to compare the degree of hypocoagulability estimated by the examined PIVKA-insensitive thromboplastin reagents.The assigned coagulation activity of different batches of the reference plasma agreed closely with experimentally obtained values. The stability of supplied batches was satisfactory as judged from the reproducibility of repeated measurements. The variability of test procedures was approximately the same on different test materials.

2020 ◽  
pp. 79-97
Author(s):  
LaTonya J. Trotter

This chapter evaluates how the presence of the nurse practitioner (NP) does not just signal changes in nursing work; it portends changes in medical work. Although real tensions exist between nurses and physicians, broadly speaking, they have worked collegially alongside one another for well over a century. This collegiality has endured despite significant changes in what both physicians and nurses do for patients. Its endurance, however, has been predicated on the one thing that has not changed: the power relations between the two. It is the difference in authority, and not just the difference in work, that undergirds the stability of the relationship between the two professions. The NP threatens to disrupt that stability. When registered nurses (RNs) become NPs, they are not just learning new skills; they are crossing lines of authority that they had previously learned to treat as constitutive of their profession. The chapter then looks at the voices and experiences of the NPs of Forest Grove Elder Services. Their narrated and actual practices negotiated physician authority in very different ways.


2019 ◽  
Vol 1 (XIX) ◽  
pp. 233-255
Author(s):  
Dariusz Rozmus

The pursuit of independence is deeply rooted in the soul of the inhabitants of Greenland. The difference in the approach to this problem amounts to the establishment of the time and the conditions on the basis of which Greenland is supposed to become independent. The island, which is the greatest island in the world, has huge deposits of minerals, including metals of rare-earth metals and uranium. On the one hand, complete independence may be an opportunity for the development for the inhabitants but on the other hand, independence may also become a source of numerous dangers. Is Greenland, a country with a slight native population, able to cope – in terms of organisation and the available staff – with the expansion of foreign capital, including the great numbers of foreign workers who are engaged in the development of industrial infrastructure? Is it not better to continue the status quo – a relationship (even a loose one) with Denmark, and thus a relationship with the European Union? A close relationship with the EU and the NATO may, in the future, be consistent with the interests of Greenlanders. In the remote and in the most recent past, Greenland was colonised by the peoples of the Far North (paleo-Eskimo and Eskimo peoples) and Scandinavians. Both Scandinavians – in the early Middle Ages – and subsequently the Inuit populated abandoned lands, lands which belonged to no one. To put it explicitly, no one stole land from anyone. Therefore it is important that in the discussion about the problem of independence which continues between Greenlanders and Danes one should not place historical problems as questions which render dialogue difficult.


2020 ◽  
Vol 150 ◽  
pp. 03001
Author(s):  
Abdelhay El Omari ◽  
Mimoun Chourak ◽  
Carlos Navvaro Ugena ◽  
Seif-Eddine Cherif ◽  
Mohamed Rougui ◽  
...  

Underground structures, such as tunnels, are vital for ensuring all kinds of transportation; and being buried under the surface makes them exposed to soil dynamics. Added to the moderate seismic activity in Morocco, the stability of tunnels is put to the test. This paper examines the interaction between the ZAM (Zaouit Ait Mellal) twin tunnels between the cities of Marrakesh and Agadir, using the Difference Element Method provided by FLAC 2D software. The acceleration is introduced as the one related to the historic event of El centro 1940 with free-field boundary conditions in the numerical model, with three configurations: tunnel 1 without tunnel 2, tunnel 2 without tunnel 1 and tunnel 1 with tunnel 2. The results of the simulations indicate that the differences values of the maximum displacement, axial force and bending moment on structural elements are very noteworthy from the configuration of the tunnel (single) to the twin tunnels in order to prove the interaction between these latter under seismic loading.


2019 ◽  
Vol 8 (1) ◽  
pp. 119-124
Author(s):  
Galina Anatolievna Fadeeva ◽  
Elena Evgenievna Boryakova

The paper deals with a research of epiparasite communities in native karst caves in the South of Nizhny Novgorod Region. Six species of bats such as Daubentons water bat, Brandts bat, whiskered bat, pond bat, northern bat and long-eared bat were examined. A Principal Component Analysis was used to identify factors influencing the composition of ectoparasites as well as the number and distribution of mites in mixed colonies of bats. As the cave and its inhabitants can be considered as a microbiotope, it is obvious that there are specific relations between inhabitants in caves. Special habitat conditions indirectly influence the parasitic systems developing there which are characterized by certain stability. Mann-Whitney U-test was used to estimate the difference between samples of animals from different habitats. Methods of nonparametric statistics didnt find significant distinctions by the hosts, years and biotopes, the bat colony and their ectoparasites can be estimated as a single complexly organized system, existing long in space and time. From all possible factorial space four factors have significant effect on systems. The contribution of the first and second factors is equal to 65% of variance (specificity of parasites to hosts and a factor of dominant species presence). In parasite communities of bats interrelations which cause successful existence of all types without the expressed competition are observed. Our results indicate a complex relationship between the parasites in the community on the one hand, and long-term existence of the community on the other hand. Each member of parasitic system has a position in factorial space. In parasite communities of bats we met only one factor-dependent species ( Spinturnix acuminatus, Sp. plecotinus, Leptotrombidium russicum ). Species that show moderate and positive, moderate and negative correlation dependence with several factors are found. For example, Spinturnix myoti , Sp. kolenatii , Macronyssus heteromorphus , etc. Heterogeneity of environmental impact on the parasitic systems which are formed in natural caves provides stability of bat parasite communities in general.


2021 ◽  
Author(s):  
Gao-hang Lv ◽  
Wei Cui ◽  
Shu Jian Wang

Abstract In the embankment widening project, the new embankment will produce large deformation due to the low degree of consolidation, which will affect the stability of the embankment. Obtaining the settlement law of embankment is the premise to ensure the stability of the embankment. In this paper, the deformation law of the new embankment is studied through the embankment model test, and the settlement calculation method of the new embankment is proposed. The model test results show that the new and old embankments have a large settlement difference during the loading process, and the maximum settlement of the new embankment is twice that of the old embankment. The lateral deformation of the new embankment is directly proportional to the vertical deformation, sliding occurs under the ultimate load, and the bearing capacity is lost. Based on the one-dimensional calculation method, the lateral deformation coefficient is introduced, and the two-dimensional embankment settlement formula is obtained. The new embankment is meshed, and the deformation of each node is calculated by the formula, and the difference between the settlement and the model test data is 6.2%, which proves the feasibility and accuracy of the calculation method.


2019 ◽  
Author(s):  
Jose Julio Gutierrez Moreno ◽  
Marco Fronzi ◽  
Pierre Lovera ◽  
alan O'Riordan ◽  
Mike J Ford ◽  
...  

<p></p><p>Interfacial metal-oxide systems with ultrathin oxide layers are of high interest for their use in catalysis. In this study, we present a density functional theory (DFT) investigation of the structure of ultrathin rutile layers (one and two TiO<sub>2</sub> layers) supported on TiN and the stability of water on these interfacial structures. The rutile layers are stabilized on the TiN surface through the formation of interfacial Ti–O bonds. Charge transfer from the TiN substrate leads to the formation of reduced Ti<sup>3+</sup> cations in TiO<sub>2.</sub> The structure of the one-layer oxide slab is strongly distorted at the interface, while the thicker TiO<sub>2</sub> layer preserves the rutile structure. The energy cost for the formation of a single O vacancy in the one-layer oxide slab is only 0.5 eV with respect to the ideal interface. For the two-layer oxide slab, the introduction of several vacancies in an already non-stoichiometric system becomes progressively more favourable, which indicates the stability of the highly non-stoichiometric interfaces. Isolated water molecules dissociate when adsorbed at the TiO<sub>2</sub> layers. At higher coverages the preference is for molecular water adsorption. Our ab initio thermodynamics calculations show the fully water covered stoichiometric models as the most stable structure at typical ambient conditions. Interfacial models with multiple vacancies are most stable at low (reducing) oxygen chemical potential values. A water monolayer adsorbs dissociatively on the highly distorted 2-layer TiO<sub>1.75</sub>-TiN interface, where the Ti<sup>3+</sup> states lying above the top of the valence band contribute to a significant reduction of the energy gap compared to the stoichiometric TiO<sub>2</sub>-TiN model. Our results provide a guide for the design of novel interfacial systems containing ultrathin TiO<sub>2</sub> with potential application as photocatalytic water splitting devices.</p><p></p>


1975 ◽  
Vol 14 (3) ◽  
pp. 370-375
Author(s):  
M. A. Akhtar

I am grateful to Abe, Fry, Min, Vongvipanond, and Yu (hereafter re¬ferred to as AFMVY) [1] for obliging me to reconsider my article [2] on the demand for money in Pakistan. Upon careful examination, I find that the AFMVY results are, in parts, misleading and that, on the whole, they add very little to those provided in my study. Nevertheless, the present exercise as well as the one by AFMVY is useful in that it furnishes us with an opportunity to view some of the fundamental problems involved in an empi¬rical analysis of the demand for money function in Pakistan. Based on their elaborate critique, AFMVY reformulate the two hypo¬theses—the substitution hypothesis and the complementarity hypothesis— underlying my study and provide us with some alternative estimates of the demand for money in Pakistan. Briefly their results, like those in my study, indicate that income and interest rates are important in deter¬mining the demand for money. However, unlike my results, they also suggest that the price variable is a highly significant determinant of the money demand function. Furthermore, while I found only a weak support for the complementarity between money demand and physical capital, the results obtained by AFMVY appear to yield a strong support for that rela¬tionship.1 The difference in results is only a natural consequence of alter¬native specifications of the theory and, therefore, I propose to devote most of this reply to the criticisms raised by AFMVY and the resulting reformulation of the two mypotheses.


2019 ◽  
Vol 67 (6) ◽  
pp. 483-492
Author(s):  
Seonghyeon Baek ◽  
Iljae Lee

The effects of leakage and blockage on the acoustic performance of particle filters have been examined by using one-dimensional acoustic analysis and experimental methods. First, the transfer matrix of a filter system connected to inlet and outlet pipes with conical sections is measured using a two-load method. Then, the transfer matrix of a particle filter only is extracted from the experiments by applying inverse matrices of the conical sections. In the analytical approaches, the one-dimensional acoustic model for the leakage between the filter and the housing is developed. The predicted transmission loss shows a good agreement with the experimental results. Compared to the baseline, the leakage between the filter and housing increases transmission loss at a certain frequency and its harmonics. In addition, the transmission loss for the system with a partially blocked filter is measured. The blockage of the filter also increases the transmission loss at higher frequencies. For the simplicity of experiments to identify the leakage and blockage, the reflection coefficients at the inlet of the filter system have been measured using two different downstream conditions: open pipe and highly absorptive terminations. The experiments show that with highly absorptive terminations, it is easier to see the difference between the baseline and the defects.


Author(s):  
Sagar Suman Panda ◽  
Ravi Kumar B.V.V.

Three new analytical methods were optimized and validated for the estimation of tigecycline (TGN) in its injection formulation. A difference UV spectroscopic, an area under the curve (AUC), and an ultrafast liquid chromatographic (UFLC) method were optimized for this purpose. The difference spectrophotometric method relied on the measurement of amplitude when equal concentration solutions of TGN in HCl are scanned against TGN in NaOH as reference. The measurements were done at 340 nm (maxima) and 410nm (minima). Further, the AUC under both the maxima and minima were measured at 335-345nm and 405-415nm, respectively. The liquid chromatographic method utilized a reversed-phase column (150mm×4.6mm, 5µm) with a mobile phase of methanol: 0.01M KH2PO4 buffer pH 3.5 (using orthophosphoric acid) in the ratio 80:20 %, v/v. The flow rate was 1.0ml/min, and diode array detection was done at 349nm. TGN eluted at 1.656min. All the methods were validated for linearity, precision, accuracy, stability, and robustness. The developed methods produced validation results within the satisfactory limits of ICH guidance. Further, these methods were applied to estimate the amount of TGN present in commercial lyophilized injection formulations, and the results were compared using the One-Way ANOVA test. Overall, the methods are rapid, simple, and reliable for routine quality control of TGN in the bulk and pharmaceutical dosage form. 


Sign in / Sign up

Export Citation Format

Share Document