Objective Skin temperatures are known to increase cutaneous sensitivity. However, it is unclear whether the amount of improved sensitivity differs depending on the protocol of heat application. Therefore, this study aimed to investigate the effects of active (treadmill walking) and passive (infrared radiator) warming of the foot sole on vibration perception thresholds. Methods Sixty healthy and injury-free subjects voluntarily participated in this study. Vibration perception thresholds (200 Hz) and plantar temperatures were measured at the hallux and 1st metatarsal head. In experiment 1, warming and mechanically stimulating the skin was achieved by walking on a treadmill for 30 min. In a follow-up study (experiment 2), external plantar heat was administered via an infrared radiator (30 min). Results In both experiments, increasing temperatures led to increased plantar sensitivity. However, the amount of improved sensitivity was greater in experiment 1, although plantar temperature increases were lower compared to experiment 2. Conclusions Warming in conjunction with mechanical stimulation seems to have a greater potential to enhance plantar sensitivity compared to external heat supply only. Significance The possible influence of mechanical stimulation and warming towards superior plantar afferent feedback highlights its importance regarding human posture and fall prevention.

Background Migrants in many European countries including Germany tend to utilize preventive measures less frequently than the majority population. Little is known about the dental health of migrants as well as about their oral health behaviour, particularly in the adult population. The aim of this study was to examine differences in the uptake of annual dental check-ups in adult migrants and non-migrants in Germany. Methods We used data from the cross-sectional survey ‘German Health Update 2010’ conducted by the Robert Koch Institute (n = 22,050). Data from 21,741 German-speaking respondents with information on the use of dental check-ups was available, of which 3404 (15.7%) were migrants. Multiple logistic regression models were applied to adjust for demographic and socioeconomic confounders, including the place of residence as well as type of health insurance. Results Migrants were generally younger, had a lower socioeconomic status and showed a lower utilization of dental check-ups. The unadjusted odds ratio (OR) for utilization was 0.67 (95%-CI = 0.61–0.73). After adjusting for demographic and socioeconomic confounders the chance only increased slightly (adjusted OR = 0.71; 95%-CI = 0.65–0.77). Conclusions The analysis shows that migration status is associated with a reduced chance of attending dental check-ups, independently of demographic and socioeconomic factors. The influence of other factors, such as type of health insurance and place of residence had also no influence on the association. Migrants are exposed to different barriers in the health care system, comprising the patient, provider and system level. Further studies need to examine the relevant barriers for the uptake of preventive dental services in order to devise appropriate migrant- sensitive measures of dental prevention.

Alloying aluminum offers the possibility of creating low-density high-entropy alloys (HEAs). Several studies that focus on the system AlCoCrFeNiTi differ in their phase determination. The effect of aluminum on the phase composition and microstructure of the compositionally complex alloy (CCA) system AlxCoCrFeNiTi was studied with variation in aluminum content (molar ratios x = 0.2, 0.8, and 1.5). The chemical composition and elemental segregation was measured for the different domains in the microstructure. The crystal structure was determined using X-ray diffraction (XRD) analysis. To identify the spatial distribution of the phases found with XRD, phase mapping with associated orientation distribution was performed using electron backscatter diffraction. This made it possible to correlate the chemical and structural conditions of the phases. The phase formation strongly depends on the aluminum content. Two different body-centered cubic (bcc) phases were found. Texture analysis proved the presence of a face-centered cubic (fcc) phase for all aluminum amounts. The hard η-(Ni, Co)3Ti phase in the x = 0.2 alloy was detected via metallographic investigation and confirmed via electron backscatter diffraction. Additionally, a centered cluster (cc) with the A12 structure type was detected in the x = 0.2 and 0.8 alloys. The correlation of structural and chemical properties as well as microstructure formation contribute to a better understanding of the alloying effects concerning the aluminum content in CCAs. Especially in the context of current developments in lightweight high-entropy alloys (HEAs), the presented results provide an approach to the development of new alloy systems.

Etwas anders soll es sein, dieses Buch zum 175-jährigen Jubiläum der Technischen Universität Chemnitz. Es erlaubt Vergleiche zwischen Generationen von Studierenden und Wissenschaftlern, die hier studiert, geforscht und gelebt haben. Es stellt Menschen vor, die im Großen und im Kleinen an der Geschichte der Hochschule mitgewirkt haben oder es noch tun. Es zeigt zudem viele Facetten der Universität und ihrer Vorläufereinrichtungen. Es gestattet aber auch den Blick in die Zukunft. Die Autoren erzählen Geschichten aus der Geschichte - und spielen dabei mit der Jubiläumszahl 175. Dazu zählen 1-Blicke in 7 Fachgebiete auf jeweils 5 Seiten sowie 1 x 7 x 5 Geschichten aus der Forschung. Außerdem ziehen sich 175 farblich hervorgehobene Superlative und Besonderheiten als "grüner Faden" durch das Buch.

Alle Akteure der TU Chemnitz wurden 2015 dazu aufgerufen sich an einem Diskurs für Nachhaltigkeit zu beteiligen. Dazu sollten sie folgende Leitfragen beantworten: „Welche Maßnahmen und Projekte setzen Sie, als Akteur (Fakultät, Forschungsverbund, administrative Einheit, universitäre Interessensgruppe), im Rahmen der „ökologischen, ökonomischen und sozialen Nachhaltigkeit“ um? Welche Definition bzw. Konzept oder Leitbild von Nachhaltigkeit legen Sie diesen Maßnahmen und Projekten zugrunde?“ Die eingereichten Beiträge sind in diesem Posterband gesammelt. / In 2015 all agents at TU Chemnitz were called to participate in a discours on sustainability. They were asked to answer the following questions: „Which steps and projects regarding „ecological, economic and social sustainability“ do you implement as an actor at the university (faculty, research association, admistrative unit or university interest group)? Which definition, concept or model do you take as a basis for these activities?“ The contributions to this call are collected in this publication.

The diethyl ester of o-phenylenebis(oxamic acid) (opbaH2Et2) was treated with an excess of RNH2 in MeOH to cause the exclusive formation of the respective o-phenylenebis(N(R)-oxamides) (opboH4R2, R = Me 1, Et 2, nPr 3) in good yields. Treatment of 1–3 with half an equivalent of [Cu2(AcO)4(H2O)2] or one equivalent of [Ni(AcO)2(H2O)4] followed by the addition of four equivalents of [nBu4N]OH resulted in the formation of mononuclear bis(oxamidato) type complexes [nBu4N]2[M(opboR2)] (M = Ni, R = Me 4, Et 5, nPr 6; M = Cu, R = Me 7, Et 8, nPr 9). By addition of two equivalents of [Cu(pmdta)(NO3)2] to MeCN solutions of 7–9, novel trinuclear complexes [Cu3(opboR2)(L)2](NO3)2 (L = pmdta, R = Me 10, Et 11, nPr 12) could be obtained. Compounds 4–12 have been characterized by elemental analysis and NMR/IR spectroscopy. Furthermore, the solid state structures of 4–10 and 12 have been determined by single-crystal X-ray diffraction studies. By controlled cocrystallization, diamagnetically diluted 8 and 9 (1%) in the host lattice of 5 and 6 (99%) (8@5 and 9@6), respectively, in the form of single crystals have been made available, allowing single crystal ESR studies to extract all components of the g-factor and the tensors of onsite CuA and transferred NA hyperfine (HF) interaction. From these studies, the spin density distribution of the [Cu(opboEt2)]2− and [Cu(opbonPr2)]2− complex fragments of 8 and 9, respectively, could be determined. Additionally, as a single crystal ENDOR measurement of 8@5 revealed the individual HF tensors of the N donor atoms to be unequal, individual estimates of the spin densities on each N donor atom were made. The magnetic properties of 10–12 were studied by susceptibility measurements versus temperature to give J values varying from −96 cm−1 (10) over −104 cm−1 (11) to −132 cm−1 (12). These three trinuclear CuII-containing bis(oxamidato) type complexes exhibit J values which are comparable to and slightly larger in magnitude than those of related bis(oxamato) type complexes. In a summarizing discussion involving experimentally obtained ESR results (spin density distribution) of 8 and 9, the geometries of the terminal [Cu(pmdta)]2+ fragments of 12 determined by crystallographic studies, together with accompanying quantum chemical calculations, an approach is derived to explain these phenomena and to conclude if the spin density distribution of mononuclear bis(oxamato)/bis(oxamidato) type complexes could be a measure of the J couplings of corresponding trinuclear complexes. / Dieser Beitrag ist aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

Deposition of silica shells onto ZnO nanoparticles (NPs) in dimethyl sulfoxide was found to be an efficient tool for terminating the growth of ZnO NPs during thermal treatment and producing stable core–shell ZnO NPs with core sizes of 3.5–5.8 nm. The core–shell ZnO–SiO2 NPs emit two photoluminescence (PL) bands centred at [similar]370 and [similar]550 nm originating from the direct radiative electron–hole recombination and defect-mediated electron–hole recombination, respectively. An increase of the ZnO NP size from 3.5 to 5.8 nm is accompanied by a decrease of the intensity of the defect PL band and growth of its radiative life-time from 0.78 to 1.49 μs. FTIR spectroscopy reveals no size dependence of the FTIR-active spectral features of ZnO–SiO2 NPs in the ZnO core size range of 3.5–5.8 nm, while in the Raman spectra a shift of the LO frequency from 577 cm−1 for the 3.5 nm ZnO core to 573 cm−1 for the 5.8 nm core is observed, which can indicate a larger compressive stress in smaller ZnO cores induced by the SiO2 shell. Simultaneous hydrolysis of zinc(II) acetate and tetraethyl orthosilicate also results in the formation of ZnO–SiO2 NPs with the ZnO core size varying from 3.1 to 3.8 nm. However, unlike the case of the SiO2 shell deposition onto the pre-formed ZnO NPs, individual core–shell NPs are not formed but loosely aggregated constellations of ZnO–SiO2 NPs with a size of 20–30 nm are. The variation of the synthetic procedures in the latter method proposed here allows the size of both the ZnO core and SiO2 host particles to be tuned. / Dieser Beitrag ist aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

viermal im Jahr erscheinender Newsletter für Freunde, Absolventen und Ehemalige der TU Chemnitz

Reihe digitaler Kalenderblätter, die historische Beiträge mit Bezug zur Region Chemnitz-Südwestsachsen veröffentlicht. / Series of digital calendar sheets to publish historical contributions related to the region of Chemnitz-South West Saxony.

In this article a Novikov engine with fluctuating hot heat bath temperature is presented. Based on this model, the performance measure maximum expected power as well as the corresponding efficiency and entropy production rate is investigated for four different stationary distributions: continuous uniform, normal, triangle, quadratic, and Pareto. It is found that the performance measures increase monotonously with increasing expectation value and increasing standard deviation of the distributions. Additionally, we show that the distribution has only little influence on the performance measures for small standard deviations. For larger values of the standard deviation, the performance measures in the case of the Pareto distribution are significantly different compared to the other distributions. These observations are explained by a comparison of the Taylor expansions in terms of the distributions’ standard deviations. For the considered symmetric distributions, an extension of the well known Curzon–Ahlborn efficiency to a stochastic Novikov engine is given.