Sr-isotope analysis of speleothems by LA-MC-ICP-MS: High temporal resolution and fast data acquisition

Speleothems are well established climate archives. A wide array of geochemical proxies, including stable isotopes and trace elements are present within speleothems to reconstruct past climate variability. However, each proxy is influenced by multiple factors, often hampering robust interpretation. Sr isotope ratios (87Sr/86Sr) can provide useful information about water residence time and water mixing in the host rock, as they are not fractionated during calcite precipitation. Laser ablation multi-collector-inductively coupled plasma mass spectrometry (LA-MC-ICP-MS) has rarely been used for determination of Sr isotope signatures in speleothems, as speleothems often do not possess appropriately high concentrations of Sr to facilitate this analysis. Yet the advantages of this approach include rapid data acquisition, higher spatial resolution, larger sample throughput and the absence of chemical treatment prior to analysis. We present LA-MC-ICP-MS Sr isotope data from two speleothems from Morocco (Grotte de Piste) and India (Mawmluh Cave), and we compare linescan and spot analysis ablation techniques along speleothem growth axes. The analytical uncertainty of our LA-MC-ICP-MS Sr data is comparable to studies conducted on other carbonate materials. The results of both ablation techniques are reproducible within analytical error, implying that this technique yields robust results when applied to speleothems. In addition, several comparative measurements of different carbonate reference materials (i.e. MACS-3, JCt-1, JCp-1), including tests with standard bracketing and comparison of the 87Sr/86Sr ratios with a nanosecond laser ablation system and a state-of-the-art femtosecond laser ablation system, highlight the robustness of the method

Serum anticholinergic activity and cerebral cholinergic dysfunction: An EEG study in frail elderly with and without delirium

<p>Abstract</p> <p>Background</p> <p>Delirium increases morbidity, mortality and healthcare costs especially in the elderly. Serum anticholinergic activity (SAA) is a suggested biomarker for anticholinergic burden and delirium risk, but the association with cerebral cholinergic function remains unclear. To clarify this relationship, we prospectively assessed the correlation of SAA with quantitative electroencephalography (qEEG) power, delirium occurrence, functional and cognitive measures in a cross-sectional sample of acutely hospitalized elderly (> 80 y) with high dementia and delirium prevalence.</p> <p>Methods</p> <p>61 consecutively admitted patients over 80 years underwent an extensive clinical and neuropsychological evaluation. SAA was determined by using radio receptor assay as developed by Tune, and standard as well as quantitative EEGs were obtained.</p> <p>Results</p> <p>15 patients had dementia with additional delirium (DD) according to expert consensus using DSM-IV criteria, 31 suffered from dementia without delirium (D), 15 were cognitively unimpaired (CU). SAA was clearly detectable in all patients but one (mean 10.9 ± 7.1 pmol/ml), but was not associated with expert-panel approved delirium diagnosis or cognitive functions. Delirium-associated EEG abnormalities included occipital slowing, peak power and alpha decrease, delta and theta power increase and slow wave ratio increase during active delirious states. EEG measures correlated significantly with cognitive performance and delirium severity, but not with SAA levels.</p> <p>Conclusion</p> <p>In elderly with acute disease, EEG parameters reliable indicate delirium, but SAA does not seem to reflect cerebral cholinergic function as measured by EEG and is not related to delirium diagnosis.</p

TEST METHODS FOR GEAR LUBRICANTS

Vrsta baznog ulja, viskoznost ulja, vrsta i sadržaj aditiva imaju značajan utjecaj na tipična oštećenja zupčanika. Općenito nije moguće jednostavno brojčano odrediti utjecaj maziva na sposobnost podnošenja opterećenja temeljem poznavanja fizikalno-kemijskih podataka o ulju. Stoga su razvijeni mnogobrojni ispitni postupci za procjenu mehaničko-tehnoloških svojstava maziva. Jednostavna i jeftina ispitivanja na probnim stolovima često pokazuju lošu korelaciju s praksom. Iz iskustva i sustavnog istraživanja moguće je pokazati da ispitivanje maziva za zupčanike može biti izvedeno na odgovarajući način samo u uređajima za ispitivanje zupčanika koja koriste specificiranu geometriju zupčanika [1]. Dugogodišnjim radom razvijen je normirani FZG probni stol sa čelnim zupčanicima s vanjskim ozubljenjem te unaprijeđen za različite vrste simulacija oštećenja zupčanika. Uobičajeni FZG uljni test A/8,3/90 široko je korišten za ocjenu svojstava ulja za industrijske zupčanike s obzirom na zaribavanje. Ulja za zupčanike vozila razine GL4 mogu se ispitivati u Step testu A10/16.6R/90, a ulja za osovine razine GL5 u Shock testu S-A10/16.6R/90. Za male brzine se može primijeniti test trošenja C/0.05/90:120. Utjecaj maziva na mikropiting ili mikrotočkastu koroziju zupčanika moguće je procijeniti pomoću kratkog testa za dodatnu provjeru GFKT-C/8,3/90. Postoje različita ispitivanja pitinga ili točkaste korozije poput testa s jednostrukim stupnjem opterećenja PT-C/9:10/90 ili testa primjene PTX-C/SNC/90. Cilj rada je opisati utjecaj maziva na različite načine oštećenja u zupčanicima, kako kvantificirati taj utjecaj u ispitnim postupcima i kako rezultate ispitivanja predstaviti kao "značajne veličine" za mazivo u postupcima ocjenjivanja sposobnosti štetnog opterećenja.Base oil type, oil viscosity, additive type and content have a strong influence on typical gear failures. In general it is not possible to quantify the lubricant influence on load carrying capacity simply from the knowledge of physical or chemical oil data. Therefore many test methods were developed for the evaluation of mechanical-technological lubricant properties. Simple low-cost bench test methods often show poor correlation with practice. From experience and systematic investigations it can be shown that testing of gear lubricants can adequately be performed only in gear test rigs using specified test gear geometry [1]. In continuous work over many years the standard FZG back-to-back gear test rig was developed and improved for different types of gear failure simulation. The standard FZG oil test A/8,3/90 is widely used for the evaluation of the scuffing properties of industrial gear oils. Automotive gear oils of GL4 level can be tested in the step test A10/16.6R/90, axle oils of GL5 level in the shock test S-A10/16.6R/90. For the slow speed regime the wear test C/0.05/90:120/12 can be applied. The influence of lubricants on the micropitting performance of gears can be evaluated in a screening short test GFKT-C/8,3/90 or in the full micropitting test GF-C/8,3/90. Different pitting tests are available as single stage test PT-C/9:10/90 or application test PTX-C/SNC/90. The aim of the paper is to describe the influence of the lubricant on the different failure modes in gears, how to quantify this influence in adequate test methods and how to introduce the results of such tests as “strength values” for the lubricant into load carrying capacity rating methods

TEST METHODS FOR GEAR LUBRICANTS

Vrsta baznog ulja, viskoznost ulja, vrsta i sadržaj aditiva imaju značajan utjecaj na tipična oštećenja zupčanika. Općenito nije moguće jednostavno brojčano odrediti utjecaj maziva na sposobnost podnošenja opterećenja temeljem poznavanja fizikalno-kemijskih podataka o ulju. Stoga su razvijeni mnogobrojni ispitni postupci za procjenu mehaničko-tehnoloških svojstava maziva. Jednostavna i jeftina ispitivanja na probnim stolovima često pokazuju lošu korelaciju s praksom. Iz iskustva i sustavnog istraživanja moguće je pokazati da ispitivanje maziva za zupčanike može biti izvedeno na odgovarajući način samo u uređajima za ispitivanje zupčanika koja koriste specificiranu geometriju zupčanika [1]. Dugogodišnjim radom razvijen je normirani FZG probni stol sa čelnim zupčanicima s vanjskim ozubljenjem te unaprijeđen za različite vrste simulacija oštećenja zupčanika. Uobičajeni FZG uljni test A/8,3/90 široko je korišten za ocjenu svojstava ulja za industrijske zupčanike s obzirom na zaribavanje. Ulja za zupčanike vozila razine GL4 mogu se ispitivati u Step testu A10/16.6R/90, a ulja za osovine razine GL5 u Shock testu S-A10/16.6R/90. Za male brzine se može primijeniti test trošenja C/0.05/90:120. Utjecaj maziva na mikropiting ili mikrotočkastu koroziju zupčanika moguće je procijeniti pomoću kratkog testa za dodatnu provjeru GFKT-C/8,3/90. Postoje različita ispitivanja pitinga ili točkaste korozije poput testa s jednostrukim stupnjem opterećenja PT-C/9:10/90 ili testa primjene PTX-C/SNC/90. Cilj rada je opisati utjecaj maziva na različite načine oštećenja u zupčanicima, kako kvantificirati taj utjecaj u ispitnim postupcima i kako rezultate ispitivanja predstaviti kao "značajne veličine" za mazivo u postupcima ocjenjivanja sposobnosti štetnog opterećenja.Base oil type, oil viscosity, additive type and content have a strong influence on typical gear failures. In general it is not possible to quantify the lubricant influence on load carrying capacity simply from the knowledge of physical or chemical oil data. Therefore many test methods were developed for the evaluation of mechanical-technological lubricant properties. Simple low-cost bench test methods often show poor correlation with practice. From experience and systematic investigations it can be shown that testing of gear lubricants can adequately be performed only in gear test rigs using specified test gear geometry [1]. In continuous work over many years the standard FZG back-to-back gear test rig was developed and improved for different types of gear failure simulation. The standard FZG oil test A/8,3/90 is widely used for the evaluation of the scuffing properties of industrial gear oils. Automotive gear oils of GL4 level can be tested in the step test A10/16.6R/90, axle oils of GL5 level in the shock test S-A10/16.6R/90. For the slow speed regime the wear test C/0.05/90:120/12 can be applied. The influence of lubricants on the micropitting performance of gears can be evaluated in a screening short test GFKT-C/8,3/90 or in the full micropitting test GF-C/8,3/90. Different pitting tests are available as single stage test PT-C/9:10/90 or application test PTX-C/SNC/90. The aim of the paper is to describe the influence of the lubricant on the different failure modes in gears, how to quantify this influence in adequate test methods and how to introduce the results of such tests as “strength values” for the lubricant into load carrying capacity rating methods

Defective Interfering RNAs: Foes of Viruses and Friends of Virologists

Defective interfering (DI) RNAs are subviral RNAs produced during multiplication of RNA viruses by the error-prone viral replicase. DI-RNAs are parasitic RNAs that are derived from and associated with the parent virus, taking advantage of viral-coded protein factors for their multiplication. Recent advances in the field of DI RNA biology has led to a greater understanding about generation and evolution of DI-RNAs as well as the mechanism of symptom attenuation. Moreover, DI-RNAs are versatile tools in the hands of virologists and are used as less complex surrogate templates to understand the biology of their helper viruses. The ease of their genetic manipulation has resulted in rapid discoveries on cis-acting RNA replication elements required for replication and recombination. DI-RNAs have been further exploited to discover host factors that modulate Tomato bushy stunt virus replication, as well as viral RNA recombination. This review discusses the current models on generation and evolution of DI-RNAs, the roles of viral and host factors in DI-RNA replication, and the mechanisms of disease attenuation

Best Practices for Biostatistical Consultation and Collaboration in Academic Health Centers

Given the increasing level and scope of biostatistics expertise needed at academic health centers today, we developed best practices guidelines for biostatistics units to be more effective in providing biostatistical support to their institutions, and in fostering an environment in which unit members can thrive professionally. Our recommendations focus on the key areas of: 1) funding sources and mechanisms; 2) providing and prioritizing access to biostatistical resources; and 3) interacting with investigators. We recommend that the leadership of biostatistics units negotiate for sufficient long-term infrastructure support to ensure stability and continuity of funding for personnel, align project budgets closely with actual level of biostatistical effort, devise and consistently apply strategies for prioritizing and tracking effort on studies, and clearly stipulate with investigators prior to project initiation policies regarding funding, lead time, and authorship