Ein 3-achsiger Simulator zur Verschleissuntersuchung von Hüftendoprothesen unter realen Randbedingungen

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.Ein entscheidendes Qualitätsmerkmal in der Hüftendoprothetik ist die Langzeitverträglichkeit der Implantate. Diese Bestrebung wird jedoch durch die nicht selten vorkommenden Osteolysenerscheinungen gefährdet, deren Grund oft auf die Abriebpartikeln der artikulierenenden Gelenkpartner zurückzuführen sind. Da der Verschleißmechanismus aufgrund individuell vielfältiger Randbedingungen sehr komplex sein könnte, sind bei der ständigen WerkstoffVerbesserung die in vivo und in vitro Verschleißuntersuchungen von großer Bedeutung. Im Gegensatz zu klinischen Beobachtungen liefern Simulatortests realitätsnahe Auskünfte unter kontrollierbaren Randbedingungen innerhalb kürzester Zeit. Dieser Beitrag stellt einen neuentwickelten dreiachsigen Hüftgelenksimulator zur Verschleißuntersuchung vor. Der Simulator ist so konzipiert, daß die natürlichen Gegebenheiten hinsichtlich Kinematik, Testumgebung und anatomischer Lage möglichst genau nachgebildet werden. Ein Verschleißtest nach ISO/DIS-14242 sowie unter besonderen Testbedingungen läßt sich mit diesem Simulator durchführen

Ein analytisches Modell für die Blutdruckübertragungsstrecke der invasiven Blutdruckmessung mit externer Flüssigkeitskopplung

Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG geförderten) Allianz- bzw. Nationallizenz frei zugänglich.This publication is with permission of the rights owner freely accessible due to an Alliance licence and a national licence (funded by the DFG, German Research Foundation) respectively.Die invasive Blutdruckmessung spielt in der Anästhesie und in der Intensivmedizin eine wichtige Rolle. Im klinischen Alltag wird vorwiegend das preisgünstige extrakorporale Blutdruckmeßverfahren mit einem externen Einwegtransducer eingesetzt. Die Qualität dieses Verfahrens hängt im wesentlichen von dem Druckübertragungsverhalten der Meßstrecke ab, welche hauptsächlich aus dem Katheter, den Verlängerungsschläuchen, der Flüssigkeitssäule und dem Transducer besteht. Zusätzlich beeinflussen in der Flüssigkeitssäule vorhandene Luftblasen die Druckübertragungsqualität. In diesem Beitrag wird eine analytische Methode zur Bestimmung der Übertragungseigenschaften dieses Blutdruckmeßsystems anhand eines erweiterten neuen Modell vorgestellt. In ihm sind alle wichtigen Bestandteile der Druckübertragungsstrecke hinsichtlich ihrer Geometrie und Materialeigenschaften berücksichtigt

ASSESSMENT OF LANDSCAPE-RECREATIONAL CAPACITY OF NORTH KAZAKHSTAN REGION

The article is concerned with the study of landscape and recreational capacity of North Kazakhstan Region (NKR). The paper presents the results of landscapes studies of North Kazakhstan Region with regard to their suitability and degree of recreation favorability. Here were studied recreational conditions and resources of the regional landscapes, as well as features of their territorial distribution and possibility of use for the recreational purposes. Recreational assessment of the region's landscapes was carried out on the basis of the developed system of criteria and their properties. The calculations were carried out taking into account the significance (weight) of each selected criterion and indicator using the method of scoring. The assessment was carried out within the boundaries of landscape areas. The obtained results made it possible to perform zoning of the territory of the region in terms of recreational capacity level, degree of favorability and possibility of organizing recreational activities of the population

CO2 electroreduction activity and dynamic structural evolution of in situ reduced nickel indium mixed oxides

In the field of CO2 electroreduction CO2ER , tuning the selectivity among diverse products remains a major challenge. Mixed metal catalysts offer possible synergetic effects which can be exploited for tuning product selectivity. We present a simple wet chemical approach to synthesize a range of nickel indium mixed oxide NiAInBOx thin films with homogeneous metal distribution. CO2 electroreduction results indicate that the NiAInBOx mixed oxide thin films can achieve high CO selectivity gt;70 in contrast with the single metal oxides NiO H2 gt;90 and In2O3 formate gt;80 . The relative composition Ni40In60Ox attained the best CO selectivity of 71 at moderate cathodic bias of amp; 8722;0.8 VRHE, while a higher cathodic bias E lt; amp; 8722;0.9 V promoted a decrease of CO in favor of formate. A detailed investigation of the Ni40In60Ox thin films following progressive stages of reduction during CO2ER revealed dynamic structural transformations strongly dependent on applied bias and electrolysis time. For the CO selective catalyst composition, at moderate cathodic bias E lt; amp; 8722;0.8 V and short electrolysis times 1 h , the catalyst is composed of nickel indium alloy grains embedded in amorphous Ni In mixed oxide as observed by electron microscopy. Extending electrolysis time at amp; 8722;0.8 V for 10 h, or increasing the applied reductive bias to amp; 8722;1.0 V, result in a complete reduction of the residual oxide film into an interconnected array of multicomponent In, Ni, Ni3In7 nanoparticles which display significantly lower CO selectivity lt;50 . Our results indicate that the persistent amorphous NiInOx oxide alloy composite material preserved in the early stages of reduction at amp; 8722;0.8 V plays a key role in CO selectivity. The highly dynamic structure observed in this catalytic system demonstrates the importance of conducting detailed structural characterization at various applied potentials to understand the impact of structural changes on the observed CO2ER selectivity trends; and thus be able to distinguish structural effects from mechanistic effects triggered by increasing the reductive bia

Constraints on a Massive Dirac Neutrino Model

We examine constraints on a simple neutrino model in which there are three massless and three massive Dirac neutrinos and in which the left handed neutrinos are linear combinations of doublet and singlet neutrinos. We examine constraints from direct decays into heavy neutrinos, indirect effects on electroweak parameters, and flavor changing processes. We combine these constraints to examine the allowed mass range for the heavy neutrinos of each of the three generations.Comment: latex, 29 pages, 7 figures (not included), MIT-CTP-221

Building Natural Product Libraries Using Quantitative Clade-Based and Chemical Clustering Strategies

The success of natural product-based drug discovery is predicated on having chemical collections that offer broad coverage of metabolite diversity. We propose a simple set of tools combining genetic barcoding and metabolomics to help investigators build natural product libraries aimed at achieving predetermined levels of chemical coverage. It was found that such tools aided in identifying overlooked pockets of chemical diversity within taxa, which could be useful for refocusing collection strategies. We have used fungal isolates identified as Alternaria from a citizen-science-based soil collection to demonstrate the application of these tools for assessing and carrying out predictive measurements of chemical diversity in a natural product collection. Within Alternaria, different subclades were found to contain nonequivalent levels of chemical diversity. It was also determined that a surprisingly modest number of isolates (195 isolates) was sufficient to afford nearly 99% of Alternaria chemical features in the data set. However, this result must be considered in the context that 17.9% of chemical features appeared in single isolates, suggesting that fungi like Alternaria might be engaged in an ongoing process of actively exploring nature’s metabolic landscape. Our results demonstrate that combining modest investments in securing internal transcribed spacer (ITS)-based sequence information (i.e., establishing gene-based clades) with data from liquid chromatography-mass spectrometry (i.e., generating feature accumulation curves) offers a useful route to obtaining actionable insights into chemical diversity coverage trends in a natural product library. It is anticipated that these outcomes could be used to improve opportunities for accessing bioactive molecules that serve as the cornerstone of natural product-based drug discovery.Open Access fees paid for in whole or in part by the University of Oklahoma Libraries.Ye

Risk factors for acute chemical releases with public health consequences: Hazardous Substances Emergency Events Surveillance in the U.S., 1996–2001

BACKGROUND: Releases of hazardous materials can cause substantial morbidity and mortality. To reduce and prevent the public health consequences (victims or evacuations) from uncontrolled or illegally released hazardous substances, a more comprehensive analysis is needed to determine risk factors for hazardous materials incidents. METHODS: Hazardous Substances Emergency Events Surveillance (HSEES) data from 1996 through 2001 were analyzed using bivariate and multiple logistic regression. Fixed-facility and transportation-related events were analyzed separately. RESULTS: For fixed-facility events, 2,327 (8%) resulted in at least one victim and 2,844 (10%) involved ordered evacuations. For transportation-related events, 759 (8%) resulted in at least one victim, and 405 (4%) caused evacuation orders. Fire and/or explosion were the strongest risk factors for events involving either victims or evacuations. Stratified analysis of fixed-facility events involving victims showed a strong association for acid releases in the agriculture, forestry, and fisheries industry. Chlorine releases in fixed-facility events resulted in victims and evacuations in more industry categories than any other substance. CONCLUSIONS: Outreach efforts should focus on preventing and preparing for fires and explosions, acid releases in the agricultural industry, and chlorine releases in fixed facilities

Objectively Measured Physical Activity Reduces the Risk of Mortality among Brazilian Older Adults.

OBJECTIVES: Use of objectively measured physical activity (PA) in older adults to assess relationship between PA and risk of all-causes mortality is scarce. This study evaluated the associations of PA based on accelerometry and a questionnaire with the risk of mortality among older adults from a city in Southern Brazil. DESIGN: A cohort study. SETTING: Urban area of Pelotas, Southern Brazil. PARTICIPANTS: A representative sample of older adults (≥60 y) from Pelotas, enrolled in 2014. MEASUREMENTS: Overall physical activity (mg), light physical activity (LPA), and moderate to vigorous physical activity (MVPA) were estimated by raw accelerometer data. The International Physical Activity Questionnaire estimated leisure time and commuting PA. Hazard ratios (excluding deaths in the first 6 mo) stratified by sex were estimated by Cox regression analysis considering adjustment for confounders. RESULTS: From the 1451 older adults interviewed in 2014, 145 died (10%) after a follow-up of an average 2.6 years. Men and women in the highest tertile of overall PA had on average a 77% and 92% lower risk of mortality than their less active counterparts (95% confidence interval [CI] = .06-.84 and 95% CI = .01-.65, respectively). The highest tertile of LPA was also related to a lower risk of mortality in individuals of both sexes (74% and 91% lower risk among men and women, respectively). MVPA statistically reduced the risk of mortality only among women (hazard ratio [HR] = .30 and HR = .07 in the second and third tertiles). Self-reported leisure-time PA was statistically associated with a lower risk of mortality only among men. Women in the highest tertiles of commuting PA showed a lower risk of mortality than those in the reference group. CONCLUSION: Accelerometry-based PA was associated with a lower risk of mortality among Brazilian older adults. Older individuals should practice any type of PA. J Am Geriatr Soc 68:137-146, 2019

Objectively Measured Physical Activity Reduces the Risk of Mortality among Brazilian Older Adults.

OBJECTIVES: Use of objectively measured physical activity (PA) in older adults to assess relationship between PA and risk of all-causes mortality is scarce. This study evaluated the associations of PA based on accelerometry and a questionnaire with the risk of mortality among older adults from a city in Southern Brazil. DESIGN: A cohort study. SETTING: Urban area of Pelotas, Southern Brazil. PARTICIPANTS: A representative sample of older adults (≥60 y) from Pelotas, enrolled in 2014. MEASUREMENTS: Overall physical activity (mg), light physical activity (LPA), and moderate to vigorous physical activity (MVPA) were estimated by raw accelerometer data. The International Physical Activity Questionnaire estimated leisure time and commuting PA. Hazard ratios (excluding deaths in the first 6 mo) stratified by sex were estimated by Cox regression analysis considering adjustment for confounders. RESULTS: From the 1451 older adults interviewed in 2014, 145 died (10%) after a follow-up of an average 2.6 years. Men and women in the highest tertile of overall PA had on average a 77% and 92% lower risk of mortality than their less active counterparts (95% confidence interval [CI] = .06-.84 and 95% CI = .01-.65, respectively). The highest tertile of LPA was also related to a lower risk of mortality in individuals of both sexes (74% and 91% lower risk among men and women, respectively). MVPA statistically reduced the risk of mortality only among women (hazard ratio [HR] = .30 and HR = .07 in the second and third tertiles). Self-reported leisure-time PA was statistically associated with a lower risk of mortality only among men. Women in the highest tertiles of commuting PA showed a lower risk of mortality than those in the reference group. CONCLUSION: Accelerometry-based PA was associated with a lower risk of mortality among Brazilian older adults. Older individuals should practice any type of PA. J Am Geriatr Soc 68:137-146, 2019