Cardiovascular risk in 159 934 frequent blood donors while addressing the healthy donor effect

Heart ◽  
2019 ◽  
Vol 105 (16) ◽  
pp. 1260-1265 ◽  
Author(s):  
Karlijn Peffer ◽  
Martin den Heijer ◽  
Wim L A M de Kort ◽  
André L M Verbeek ◽  
Femke Atsma
Keyword(s):  
Cardiovascular Risk ◽  
High Frequency ◽  
Healthy Donor ◽  
Blood Donors ◽  
Cox Regression ◽  
Blood Donation ◽  
Low Frequency ◽  
Sensitivity Analyses ◽  
Hospital Data ◽  
Dutch Hospital

ObjectiveTo investigate whether regular blood donation decreases cardiovascular risk.MethodsAll 159 934 Dutch whole-blood donors with an active donation career of at least 10 years were categorised into sex-specific donation tertiles based on the number of donations during this 10-year qualification period. Cardiovascular endpoints were based on hospital discharge diagnoses and death certificates from Dutch Hospital Data and Statistics Netherlands and occurring after the 10-year qualification period. Cox regression was used to estimate the age-adjusted and starting year-adjusted hazard rate ratio (HRR).ResultsFemale high-frequency blood donors had a reduced cardiovascular morbidity (HRR=0.91, 95% CI 0.85 to 0.98) compared with low-frequency blood donors. No effect was observed in men (HRR=1.00, 95% CI 0.95 to 1.05). To rule out a residual healthy donor effect (HDE), additional sensitivity analyses using a 5-year qualification period were conducted. The results supported the absence of a residual HDE.ConclusionsThis study showed a protective effect of long-term, high-frequency blood donation against cardiovascular disease. This effect was only observed in women and not in men.

scholarly journals STATUS OF LIPID PEROXIDATION AND TOTAL ANTIOXIDANT CAPACITY IN REGULAR VOLUNTARY BLOOD DONORS

2011 ◽  
Vol 01 (04) ◽  
pp. 03-06
Author(s):  
Suchetha Kumari ◽  
Jayaprakash Shetty K. ◽  
Sharada V. ◽  
◽  
Keyword(s):  
Lipid Peroxidation ◽  
Antioxidant Capacity ◽  
Total Antioxidant Capacity ◽  
Blood Donors ◽  
Blood Donation ◽  
Cell Damage ◽  
Low Frequency ◽  
Lipid Peroxidation Product ◽  
Total Antioxidant ◽  
Peroxidation Product

AbstractOxygen free radicals and products of oxidative cell damage are known as biomarkers that escalate in the pathophysiology of many diseases. The aim of this study is to evaluate association between blood donation and total antioxidant capacity and lipid peroxidation product malondialdehyde(MDA). The levels of MDA and total antioxidant capacity(TAC) were studied in serum of 90 male voluntary blood donors aged from 20 to 45 years attending K. S. Hegde charitable hospital, Blood bank, for determination of lipid peroxidation and antioxidant status, respectively. The donors were divided into nine groups depending on number of blood donation. With increase in number of blood donation the serum MDA level were significantly reduced (p>0.01) but total antioxidant activity was significantly increased (p>0.01). High frequency of blood donors had evidence of decreased lipid peroxidation and enhanced activity of total antioxidants when compared with low frequency blood donors. which can be considered as one of the fringe benefits of regular blood donation.

Simulations of high-resolution images of amorphous silicon films

1986 ◽  
Vol 44 ◽  
pp. 544-545
Author(s):  
G. Y. Fan ◽  
J. M. Cowley
Keyword(s):  
Electron Microscope ◽  
High Frequency ◽  
Fourier Transformation ◽  
Amorphous Materials ◽  
Low Frequency ◽  
Chromatic Aberration ◽  
Structure Information ◽  
Frequency Components ◽  
High Resolution Images ◽  
Spatial Frequency Spectrum

It is well known that the structure information on the specimen is not always faithfully transferred through the electron microscope. Firstly, the spatial frequency spectrum is modulated by the transfer function (TF) at the focal plane. Secondly, the spectrum suffers high frequency cut-off by the aperture (or effectively damping terms such as chromatic aberration). While these do not have essential effect on imaging crystal periodicity as long as the low order Bragg spots are inside the aperture, although the contrast may be reversed, they may change the appearance of images of amorphous materials completely. Because the spectrum of amorphous materials is continuous, modulation of it emphasizes some components while weakening others. Especially the cut-off of high frequency components, which contribute to amorphous image just as strongly as low frequency components can have a fundamental effect. This can be illustrated through computer simulation. Imaging of a whitenoise object with an electron microscope without TF limitation gives Fig. 1a, which is obtained by Fourier transformation of a constant amplitude combined with random phases generated by computer.

SEM image sharpness analysis

1996 ◽  
Vol 54 ◽  
pp. 142-143
Author(s):  
M. T. Postek ◽  
A. E. Vladar
Keyword(s):  
High Frequency ◽  
Low Frequency ◽  
Quantitative Information ◽  
Primary Electron ◽  
Image Sharpness ◽  
Critical Dimensions ◽  
Sem Image ◽  
Frequency Changes ◽  
Electron Microscopes ◽  
Scanning Electron

Fully automated or semi-automated scanning electron microscopes (SEM) are now commonly used in semiconductor production and other forms of manufacturing. The industry requires that an automated instrument must be routinely capable of 5 nm resolution (or better) at 1.0 kV accelerating voltage for the measurement of nominal 0.25-0.35 micrometer semiconductor critical dimensions. Testing and proving that the instrument is performing at this level on a day-by-day basis is an industry need and concern which has been the object of a study at NIST and the fundamentals and results are discussed in this paper.In scanning electron microscopy, two of the most important instrument parameters are the size and shape of the primary electron beam and any image taken in a scanning electron microscope is the result of the sample and electron probe interaction. The low frequency changes in the video signal, collected from the sample, contains information about the larger features and the high frequency changes carry information of finer details. The sharper the image, the larger the number of high frequency components making up that image. Fast Fourier Transform (FFT) analysis of an SEM image can be employed to provide qualitiative and ultimately quantitative information regarding the SEM image quality.

Real Ear Sound Pressure Levels Developed by Three Portable Stereo System Earphones

1992 ◽  
Vol 1 (4) ◽  
pp. 52-55 ◽  
Author(s):  
Gail L. MacLean ◽  
Andrew Stuart ◽  
Robert Stenstrom
Keyword(s):  
High Frequency ◽  
Sound Pressure ◽  
Low Frequency ◽  
Test System ◽  
Output Frequency ◽  
Frequency Effects ◽  
Adult Men ◽  
Frequency Responses ◽  
Significant Difference ◽  
Sound Pressure Levels

Differences in real ear sound pressure levels (SPLs) with three portable stereo system (PSS) earphones (supraaural [Sony Model MDR-44], semiaural [Sony Model MDR-A15L], and insert [Sony Model MDR-E225]) were investigated. Twelve adult men served as subjects. Frequency response, high frequency average (HFA) output, peak output, peak output frequency, and overall RMS output for each PSS earphone were obtained with a probe tube microphone system (Fonix 6500 Hearing Aid Test System). Results indicated a significant difference in mean RMS outputs with nonsignificant differences in mean HFA outputs, peak outputs, and peak output frequencies among PSS earphones. Differences in mean overall RMS outputs were attributed to differences in low-frequency effects that were observed among the frequency responses of the three PSS earphones. It is suggested that one cannot assume equivalent real ear SPLs, with equivalent inputs, among different styles of PSS earphones.

Evaluation of Special Hearing Aids for Deaf Children

1971 ◽  
Vol 36 (4) ◽  
pp. 527-537 ◽  
Author(s):  
Norman P. Erber
Keyword(s):  
Hearing Aids ◽  
High Frequency ◽  
Hearing Aid ◽  
Low Frequency ◽  
Acoustic Stimulation ◽  
Deaf Children ◽  
Frequency Range ◽  
Frequency Limit ◽  
Unpublished Studies ◽  
Published Research

Two types of special hearing aid have been developed recently to improve the reception of speech by profoundly deaf children. In a different way, each special system provides greater low-frequency acoustic stimulation to deaf ears than does a conventional hearing aid. One of the devices extends the low-frequency limit of amplification; the other shifts high-frequency energy to a lower frequency range. In general, previous evaluations of these special hearing aids have obtained inconsistent or inconclusive results. This paper reviews most of the published research on the use of special hearing aids by deaf children, summarizes several unpublished studies, and suggests a set of guidelines for future evaluations of special and conventional amplification systems.

F.VIII R:Ag in Hepatitis

1979 ◽  
Author(s):  
R. Kotitschke ◽  
J. Scharrer
Keyword(s):  
Chronic Hepatitis ◽  
Blood Donors ◽  
Blood Donation ◽  
Normal Population ◽  
Rabbit Antiserum ◽  
Two Dimensional ◽  
Plastic Plate ◽  
Significant Difference ◽  
Acute Hepatitis B ◽  
The One

F.VIII R:Ag was determined by quantitative immunelectrophoresis (I.E.) with a prefabricated system. The prefabricated system consists of a monospecific f.VIII rabbit antiserum in agarose on a plastic plate for the one and two dimensional immunelectrophoresis. The lognormal distribution of the f.VIII R:Ag concentration in the normal population was confirmed (for n=70 the f.VIII R:Ag in % of normal is = 95.4 ± 31.9). Among the normal population there was no significant difference between blood donors (one blood donation in 8 weeks; for n=43 the f.VIII R:Ag in % of normal is = 95.9 ± 34.0) and non blood donors (n=27;f.VIII R:Ag = 94.6 ± 28.4 %). The f.VIII R:Ag concentration in acute hepatitis B ranged from normal to raised values (for n=10, a factor of 1.8 times of normal was found) and was normal again after health recovery (n=10, the factor was 1.0). in chronic hepatitis the f.VIII R:Ag concentration was raised in the majority of the cases (for n=10, the factor was 3.8). Out of 22 carrier sera 20 showed reduced, 2 elevated levels of the f.VIII R:Ag concentration. in 5 sera no f.VIII R:Ag could be demonstrated. The f.VIII R:Ag concentration was normal for n=10, reduced for n=20 and elevated for n=6 in non A-non B hepatitis (n=36). Contrary to results found in the literature no difference in the electrophoretic mobility of the f.VIII R:Ag was found between hepatitis patients sera and normal sera.

Efeitos do Método Pilates sobre a variabilidade da frequência cardíaca, flexibilidade e variáveis antropométricas em indivíduos sedentários

2016 ◽  
Vol 17 (1) ◽  
pp. 66
Author(s):  
Maria Lina Silva Leite
Keyword(s):  
High Frequency ◽  
Low Frequency

O objetivo deste estudo foi avaliar os efeitos do Método Pilates sobre a variabilidade da frequência cardíaca, na flexibilidade e nas variáveis antropométricas em indivíduos sedentários. O presente estudo contou com 14 voluntárias do sexo feminino, na faixa etária entre 40 e 55 anos, que realizaram 20 sessões de exercícios do Método Pilates, duas vezes por semana, com duração de 45 minutos cada sessão, dividida em três fases: repouso, exercício e recuperação. As variáveis estudadas foram: os dados antropométricos, flexibilidade avaliada utilizando o teste de sentar-e-alcançar com o Banco de Wells, e intervalos R-R usando um cardiotacômetro. O processamento dos sinais da frequência cardíaca foi efetuado em ambiente MatLab 6.1®, utilizando a TWC. Os dados coletados foram submetidos ao teste de normalidade de Shapiro Wilk e foi utilizado o teste de Wilcoxon e Anova One Way (α = 0,05). Nos resultados, observou-se que não houve diferenças significativas entre os valores antropométricos e de frequência cardíaca, porém houve aumento da flexibilidade com o treinamento. Comparando a primeira e a vigésima sessão com relação aos parâmetros low frequency (LF), high frequency (HF), e relação LF/HF, não houve diferença na fase de repouso e foram constatadas diferenças significativas de LF (p = 0,04) e HF (p = 0,04) na fase de exercício e diferença significativa de LF/HF (p = 0,05) na fase de recuperação. Comparando os parâmetros nos períodos de repouso, exercícios e recuperação durante a primeira sessão e durante a vigésima sessão, não houve diferença significativa nos parâmetros LF, HF e LF/HF. Pode-se concluir que, em relação à flexibilidade, foi observada uma melhora significativa, enquanto a análise da frequência cardíaca caracterizou a intensidade do exercício de 50% da capacidade funcional das voluntárias. Em relação aos parâmetros LF, HF e LF/HF foram observados um aumento da variabilidade da frequência cardíaca, provavelmente produto da atividade do Método Pilates. A Transformada Wavelet (TWC) mostrou-se um Método adequado para as análises da variabilidade da frequência cardíaca.Palavras-chave: frequência cardíaca, Transformada Wavelet, Pilates.

Dynamics of the processes in metal machining

1998 ◽  
Vol 2 ◽  
pp. 115-122
Author(s):  
Donatas Švitra ◽  
Jolanta Janutėnienė
Keyword(s):  
High Frequency ◽  
Machine Tools ◽  
Metal Cutting ◽  
Cutting Tool ◽  
Low Frequency ◽  
Metal Cutting Machine ◽  
Cutting Machine ◽  
Metal Machining

In the practice of processing of metals by cutting it is necessary to overcome the vibration of the cutting tool, the processed detail and units of the machine tool. These vibrations in many cases are an obstacle to increase the productivity and quality of treatment of details on metal-cutting machine tools. Vibration at cutting of metals is a very diverse phenomenon due to both it’s nature and the form of oscillatory motion. The most general classification of vibrations at cutting is a division them into forced vibration and autovibrations. The most difficult to remove and poorly investigated are the autovibrations, i.e. vibrations arising at the absence of external periodic forces. The autovibrations, stipulated by the process of cutting on metalcutting machine are of two types: the low-frequency autovibrations and high-frequency autovibrations. When the low-frequency autovibration there appear, the cutting process ought to be terminated and the cause of the vibrations eliminated. Otherwise, there is a danger of a break of both machine and tool. In the case of high-frequency vibration the machine operates apparently quiently, but the processed surface feature small-sized roughness. The frequency of autovibrations can reach 5000 Hz and more.

Calculation-and-experimental estimation of the role of the frequency ratio in changing the endurance at two-frequency deformation modes

2019 ◽  
Vol 85 (1(I)) ◽  
pp. 64-71 ◽  
Author(s):  
M. M. Gadenin
Keyword(s):  
High Frequency ◽  
Experimental Studies ◽  
Low Frequency ◽  
Reduction Factor ◽  
Single Frequency ◽  
Cyclic Loads ◽  
Small Ratio ◽  
Harmonic Components ◽  
Deformation Modes

The cycle configuration at two-frequency loading regimes depends on the number of parameters including the absolute values of the frequencies and amplitudes of the low-frequency and high-frequency loads added during this mode, the ratio of their frequencies and amplitudes, as well as the phase shift between these harmonic components, the latter having a significant effect only with a small ratio of frequencies. Presence of such two-frequency regimes or service loading conditions for parts of machines and structures schematized by them can significantly reduce their endurance. Using the results of experimental studies of changes in the endurance of a two-frequency loading of specimens of cyclically stable, cyclically softened and cyclically hardened steels under rigid conditions we have shown that decrease in the endurance under the aforementioned conditions depends on the ratio of frequencies and amplitudes of operation low-frequency low-cycle and high-frequency vibration stresses, and, moreover, the higher the level of the ratios of amplitudes and frequencies of those stacked harmonic processes of loading the greater the effect. It is shown that estimation of such a decrease in the endurance compared to a single frequency loading equal in the total stress (strains) amplitudes can be carried out using an exponential expression coupling those endurances through a parameter (reduction factor) containing the ratio of frequencies and amplitudes of operation cyclic loads and characteristic of the material. The reduction is illustrated by a set of calculation-experimental curves on the corresponding diagrams for each of the considered types of materials and compared with the experimental data.

RISKS OF ANEMIA DEVELOPMENT IN DONORS ACCORDING TO INHERITED PREDISPOSITION AND REGULARITY OF BLOOD DONATION

2020 ◽  
pp. 72-83
Author(s):  
I.M. Vorotnikov ◽  
V.A. Razin ◽  
I.M. Lamzin ◽  
M.N. Sokolova ◽  
M.E. Khapman ◽  
...  
Keyword(s):  
Blood Donors ◽  
Blood Donation ◽  
Hla Antigens ◽  
Hla Typing ◽  
Main Role ◽  
Inherited Predisposition ◽  
Group 2 ◽  
Student’S T ◽  
A Prospective Study ◽  
Group 1

Anemia is one of the most common complications of blood donation. Thus, the objective of the paper was to assess the risks of anemia development in donors according to the regularity of donation and inherited predisposition. Materials and Methods. The authors carried out a prospective study, which included 241 blood donors, using random sampling and case-control techniques. Depending on blood donation frequency, the donors were divided into 2 groups: Group 1 consisted of 122 people (51.5 %) frequently donating blood; Group 2 included 119 people (48. 5 %) rarely donating blood. We studied the initial indicators of a general blood test and the same indicators a year after the first blood donation. Additionally, we performed HLA typing of donors. Statistica v. 8.0 software package (Stat Soft Inc., USA) was used for statistical analysis. To compare two independent samples, we used a nonparametric Mann-Whitney U-test and a parametric Student’s t-test (depending on the type of distribution). To assess anemia risks, the odds ratio was calculated. Results. One year after the first blood donation, anemia was diagnosed in 13 people (10.6 %) in Group 1 and in 7 people (5.9 %) in Group 2 (p=0.179). A11 and B7 HLA antigens did not increase anemia risks in group 1 (OS=1.257 (95 % CI 0.318–4.973) and OS=0.240 (95 % CI 0.051–1.134, respectively). HLA-antigens A11 and B7 did not increase anemia risks in Group 1 (OR=1.257 (95 % CI 0.318-4.973) and OR=0.240 (95 % CI 0.051–1.134), respectively). In group 2, antigen-A11 was also an insignificant factor (OS=2.902 (95 % CI 0.606-13.889)) for anemia development. Whereas, antigen-B7 increased anemia risks by 14 times (OS=14.364 (95 % CI 1.644-124.011)). Conclusion. In rare blood donors, it is the genetic factor that plays the main role in anemia development. High prevalence rates of anemia in frequent blood donors are probably determined by other factors. Keywords: anemia, blood donors, HLA typing. Механизмы развития анемий и факторы, их индуцирующие, остаются до конца не изученными. Целью исследования стало изучение риска развития анемии у доноров крови в зависимости от частоты донации и наличия наследственной предрасположенности к развитию анемии. Материалы и методы. Проведено проспективное исследование, выполненное методами случайной выборки и «случай-контроль», в которое вошел 241 донор крови. В зависимости от частоты сдачи доноры были поделены на 2 группы: группу 1 составили 122 чел. (51,5 %), часто сдающие кровь; группу 2 – 119 чел. (48,5 %), редко сдающих кровь. Изучались исходные показатели общего анализа крови и через год от начала донации. Дополнительно проводилось HLA-типирование доноров. Статистический анализ осуществлялся с применением программы Statistica v. 8.0 (Stat Soft Inc., США). Для сравнения двух независимых выборок использовался непараметрический U-критерий Манна–Уитни и параметрический t-критерий Стьюдента (в зависимости от типа распределения). Для оценки риска возникновения анемии рассчитывалось отношение шансов. Результаты. Через год с момента первой сдачи крови в группе 1 выявлено 13 чел. (10,6 %) с анемией, в группе 2 – 7 чел. (5,9 %) (р=0,179). Наличие HLA-антигенов А11 и B7 не повышало риск развития анемии в группе 1 (ОШ=1,257 (95 % ДИ 0,318–4,973) и ОШ=0,240 (95 % ДИ 0,051–1,134 соответственно). В группе 2 наличие гена А11 также являлось незначимым фактором (ОШ=2,902 (95 % ДИ 0,606–13,889), присутствие гена В7 в 14 раз повышало риск развития анемии (ОШ=14,364 (95 % ДИ 1,664–124,011). Выводы. Высокий риск развития анемии у редко сдающих кровь доноров обусловливается генетическими факторами. Высокая распространённость анемии у часто сдающих кровь доноров, вероятно, определяется другими факторами. Ключевые слова: анемия, доноры крови, HLA-типирование.

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