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showing 10 items of 21438 documents
Pyöräilyn hyötysuhteiden yhteyksiä
2017
Pyöräilytyössä hyötysuhdetta (ulkoisen polkemistyön suhdetta kokonaisenergiankulutukseen)on helppo tutkia ja tällaiseen metaboliseen tehokkuuteen onkin määritelty monia erilaisia mittareita. Fysiologisten ja biomekaanisten muuttujien vaikutuksia näihin eri tavoin määritettyihin hyötysuhteisiin tunnetaan hyvinkin, mutta tätä ennen ei olla juurikaan tutkittu mitkä ovat eri tavoin määriteltyjen hyötysuhteiden keskinäiset suhteet. Tutkimukseen osallistui 14 perustervettä fyysisesti aktiivista 31 ± 6 vuotiasta mies- (n = 12)ja naistutkittavaa (n = 2). Tutkittaville laskettiin kuusi erilaista metabolisen tehokkuuden arvoa: vakioteholla (150 W) kokonais- ja nettohyötysuhde, kaksi työhyötysuhdetta …
Kognitiivinen kehitys sekä metamuistin, itsearvioidun terveyden ja mielialan yhteys kognitiiviseen suorituskykyyn iäkkäillä ihmisillä
2006
Tutkimuksessa tarkasteltiin ikääntyvien kognitiivista kehitystä 75. ja 90. ikävuoden välillä. Tutkimuksessa selvitettiin myös miten kognitiivinen suorituskyky (MMSE-, älykkyys- ja muistipistemäärä) oli yhteydessä muistin, terveyden ja mielialan itsearvioihin naisilla ja miehillä. Tutkittavat olivat Ikivihreät-projektiin osallistuneita vuonna 1914 syntyneitä jyväskyläläisiä (n=49-355), ja heitä arvioitiin viiden vuoden välein vuosina 1989–2004 tutkittavien ollessa 75-, 80-, 85- ja 90-vuotiaita. Kognitiivista suoriutumista arvioitiin MMSE-testillä ja neuropsykologisista ja psykometrisista testeistä muodostetuilla älykkyys- ja muistipistemäärillä. Muistin itsearviota tutkittiin metamuistikysel…
Different-day and same-session combined strength and endurance training : adaptations in neuromuscular and cardiorespiratory performance, body compos…
2017
This thesis investigated 1) acute neuromuscular and hormonal responses to combined strength and endurance loadings with different orders and their long-term adaptations (women), 2) adaptations in neuromuscular, hormonal, cardiorespiratory and health variables following 24 weeks of volume-equated protocols of combined training (men and women). Subjects were assigned to one of three groups: strength and endurance training on different days (DD: men n=21, women n=18), training in the same-session with either endurance before strength (ES: men n=16, women n=15) or vice versa (SE: men n=18, women n=14). DD trained 4-6 d·wk-1 with strength and endurance on alternating days. ES and SE trained 2-3 …
Landfill operation and waste management procedures in the reduction of methane and leachate pollutant emissions from municipal solid waste landfills
2002
The objective of the present research was to find ways of minimising emissions from municipal solid waste (MSW) landfills by means of laboratory experiments.
Copper-hydride nanoclusters with enhanced stability by N-heterocyclic carbenes
2021
AbstractCopper-hydrides have been intensively studied for a long time due to their utilization in a variety of technologically important chemical transformations. Nevertheless, poor stability of the species severely hinders its isolation, storage and operation, which is worse for nano-sized ones. We report here an unprecedented strategy to access to ultrastable copper-hydride nanoclusters (NCs), namely, using bidentate N-heterocyclic carbenes as stabilizing ligands in addition to thiolates. In this work, a simple synthetic protocol was developed to synthesize the first large copper-hydride nanoclusters (NCs) stabilized by N-heterocyclic carbenes (NHCs). The NC, with the formula of Cu31(RS)2…
Thiol-Stabilized Atomically Precise, Superatomic Silver Nanoparticles for Catalyzing Cycloisomerization of Alkynyl Amines
2018
Abstract Both the electronic and surface structures of metal nanomaterials play critical roles in determining their chemical properties. However, the non-molecular nature of conventional nanoparticles makes it extremely challenging to understand the molecular mechanism behind many of their unique electronic and surface properties. In this work, we report the synthesis, molecular and electronic structures of an atomically precise nanoparticle, [Ag206L72]q (L = thiolate, halide; q = charge). With a four-shell Ag7@Ag32@Ag77@Ag90 Ino-decahedral structure having a nearly perfect D5h symmetry, the metal core of the nanoparticle is co-stabilized by 68 thiolate and 4 halide ligands. Both electroche…
Electronic shell structures in bare and protected metal nanoclusters
2016
This short review discusses the concept of the electronic shell structure in the context of metal nanoclusters. Electronic shell structure is a natural consequence of quantization of fermionic states in a quantum confinement, where the symmetry of the confining potential creates energetically close-lying sets of states that reflect the symmetry of the potential. It was introduced in cluster physics in early 1980s and initially influenced greatly by the related model of nuclear shell structure from 1950’s. Three application areas are discussed consisting of free gas phase clusters, clusters supported by insulating oxides or oxide thin films, and clusters that are synthesized by wet chemistry…
Structural Motifs of Alkali Metal Superbases in Non‐coordinating Solvents
2020
Abstract Lochmann–Schlosser superbases (LSB) are a standard reagent in synthetic chemistry to achieve an exchange of a proton on an organic framework with an alkali metal cation, which in turn can be replaced by a wide range of electrophilic groups. In standard examples, the deprotonating reagent consists of an equimolar mixture of n‐butyllithium and potassium t‐butoxide. However, the nature of the reactive species could not be pinned down either for this composition or for similar mixtures with comparable high reactivity. Despite the poor solubility and the fierce reactivity, some insights into this mixture were achieved by some indirect results, comparison with chemically related systems,…
Catalytic applications of TiO2
2021
Abstract The use of TiO2 as heterogeneous catalyst and/or active support for metals or other oxides is here reported. Many reactions of industrial relevance involve, in fact, titania-based catalysts, among them, NOx abatement, Fischer–Tropsch and water–gas shift, Deacon and Claus processes, hydrodesulfurizations and hydrogenations, selective reductions and selective oxidations. This chapter aims to discuss the main applications of TiO2, in its different forms, as effective support or catalyst for thermocatalytic and photo-thermocatalytic reactions, focusing on the role of its structural and physicochemical properties on the catalytic performance (activity, selectivity, stability).
Determination of glyphosate and its metabolite aminomethylphosphonic acid in fruit juices using supported-liquid membrane preconcentration method wit…
2005
Abstract The application of supported-liquid membrane (SLM) technique for effective extraction of N -(phosphonomethyl)glycine (glyphosate) and its primary metabolite aminomethylphosphonic acid (AMPA) from juices (orange, grapefruit, apple and blackcurrant) in combination with HPLC-UV detection after derivatization with p -toluenesulphonyl chloride (TsCl) is presented. The influence of various parameters such as the composition of acceptor phase, flow-rate, concentration of analytes, on the performance of extraction procedure, was studied. It was shown that by appropriate manipulation of SLM parameters the level of detection could be significantly improved. The influence of SLM conditions on…