Bindung von Auszubildenden in der Finanzdienstleistungsbranche - Strukturgleichungsmodellierung mittels der Partial Least Squares-Methode

Die Bindung guter Mitarbeiter stellt für Unternehmen in Zeiten des demographischen Wandels und eines damit einhergehenden Fachkräftemangels eine zentrale Herausforderung dar. Die Generation Y bzw. Auszubildende, die dieser Generation angehören, zeigen eine besonders hohe Wechselbereitschaft. Organisationales Commitment (OC) ist daher in der Psychologie und angrenzenden Wissenschaften eine zentrale Untersuchungsvariable. Die vorliegende Arbeit spezifizierte und erweiterte das OC-Rahmenmodell nach Felfe (2008) um verschiedene Personen- und Organisationsvariablen, wie die Big Five, die Selbstwirksamkeitserwartung und Angebote einer Organisation. Zudem wurden die Erwartungen und Erfahrungen einer Person sowie die Diskrepanz davon (met expectations), die Bedeutung der Tätigkeit und die Rolle der Stimmung untersucht. Ziel war es, die Zusammenhänge der Variablen zu verstehen und Aussagen über Veränderungen zu treffen. In einem Zeitraum von drei Jahren wurden zu sechs Messzeitpunkten insgesamt 1277 Fragebögen von Auszubildenden aus Sparkassen in Baden-Württemberg ausgefüllt. Mittels der Partial Least Squares-Methode, die die Variablen in einem Strukturgleichungsmodell betrachtet, wurden die Ergebnisse ausgewertet. Es zeigte sich zum einen ein stärkerer Einfluss der Organisation auf die Erfahrungen eines Mitarbeiters im Vergleich zu den Persönlichkeitsmerkmalen. Zum anderen prägten die Erfahrungen das OC stärker als die Erwartungen oder die met expectations. OC war neben der Arbeitszufriedenheit der beste Prädiktor für die Bleibeabsicht. Die Bereiche Arbeitgeberimage, Weiterentwicklungsmöglichkeiten, Aufgaben und Führung konnten als wesentliche Entwicklungsfelder für das OC ausgemacht werden. Neben diesem theoretischen Erkenntnisgewinn weist die Arbeit einen hohen praktischen Nutzen auf, da konkrete Maßnahmen zur Bindung von Auszubildenden und der Generation Y formuliert werden konnten

The mitochondrial Na+/Ca2+ exchanger upregulates glucose dependent Ca2+ signalling linked to insulin secretion.

Mitochondria mediate dual metabolic and Ca(2+) shuttling activities. While the former is required for Ca(2+) signalling linked to insulin secretion, the role of the latter in β cell function has not been well understood, primarily because the molecular identity of the mitochondrial Ca(2+) transporters were elusive and the selectivity of their inhibitors was questionable. This study focuses on NCLX, the recently discovered mitochondrial Na(+)/Ca(2+) exchanger that is linked to Ca(2+) signalling in MIN6 and primary β cells. Suppression either of NCLX expression, using a siRNA construct (siNCLX) or of its activity, by a dominant negative construct (dnNCLX), enhanced mitochondrial Ca(2+) influx and blocked efflux induced by glucose or by cell depolarization. In addition, NCLX regulated basal, but not glucose-dependent changes, in metabolic rate, mitochondrial membrane potential and mitochondrial resting Ca(2+). Importantly, NCLX controlled the rate and amplitude of cytosolic Ca(2+) changes induced by depolarization or high glucose, indicating that NCLX is a critical and rate limiting component in the cross talk between mitochondrial and plasma membrane Ca(2+) signalling. Finally, knockdown of NCLX expression was followed by a delay in glucose-dependent insulin secretion. These findings suggest that the mitochondrial Na(+)/Ca(2+) exchanger, NCLX, shapes glucose-dependent mitochondrial and cytosolic Ca(2+) signals thereby regulating the temporal pattern of insulin secretion in β cells

ZnR/GPR39 upregulation of K+/Cl−-cotransporter 3 in tamoxifen resistant breast cancer cells

Expression of the zinc receptor, ZnR/GPR39, is increased in higher grade breast cancer tumors and cells. Zinc, its ligand, is accumulated at larger concentrations in the tumor tissue and can therefore activate ZnR/GPR39-dependent Ca2+ signaling leading to tumor progression. The K+/Cl− co-transporters (KCC), activated by intracellular signaling, enhance breast cancer cell migration and invasion. We asked if ZnR/GPR39 enhances breast cancer cell malignancy by activating KCC. Activation of ZnR/GPR39 by Zn2+ upregulated K+/Cl− co-transport activity, measured using NH4+ as a surrogate to K+ while monitoring intracellular pH. Upregulation of NH4+ transport was monitored in tamoxifen resistant cells with functional ZnR/GPR39-dependent Ca2+ signaling but not in MCF-7 cells lacking this response. The NH4+ transport was Na+-independent, and we therefore focused on KCC family members. Silencing of KCC3, but not KCC4, expression abolished Zn2+-dependent K+/Cl− co-transport, suggesting that KCC3 is mediating upregulated NH4+ transport. The ZnR/GPR39-dependent KCC3 activation accelerated scratch closure rate, which was abolished by inhibiting KCC transport with [(DihydroIndenyl) Oxy] Alkanoic acid (DIOA). Importantly, silencing of either ZnR/GPR39 or KCC3 attenuated Zn2+-dependent scratch closure. Thus, a novel link between KCC3 and Zn2+, via ZnR/GPR39, promotes breast cancer cell migration and proliferation

Model optimiacije ribočuvarske službe u cilju zaštite vodenih sistema

Važan segment svakog upravljačkog sistema su ljudski resursi i pronalaženje modaliteta da se isti koriste racionalno i ekonomično. Cilj rada je da se na konkretnom primeru određivanja parametara koji utiču na optimalan broj ribočuvara po prvi put prikaže mogućnost primene skalarnog metoda ocenjivanja (SMO) u praktičnom upravljanju ribolovnim vodama. Kombinovanjem metoda SMO sa metodom analitičko hijerarhijskog procesa, moguće je upravljačke odluke na objektivan način valorizovati i učiniti metodološki primenljivim prilikom određivanja optimalnog broja ribočuvarske službe. Objektivnost definisanja kriterijuma i izbor alternativa u odnosu na postavljeni cilj zavise od dostupnih inicijalnih informacija i iskustva donosioca odluka, ali je ovaj nedostatak moguće otkloniti donošenjem alternativnih rešenja zasnovanim na principima višekriterijumske analize i matematičkog modelovanja. U ovom radu SMO metod je prezentovan na primeru organizovanja ribočuvarske službe i daje mogućnost da se ciljni parametri odrede u kvalitativnom i kvantitativnom pogledu, kroz optimalizaciju broja potrebnih ribočuvara. Rezultati ovog rada ukazuju na potrebu inoviranja postojećih metoda pri donošenju upravljačkih odluka po pitanju organizovanja ribočuvarske službe. Iako na prvi pogled ovaj metod izgleda komplikovan, primenom odgovarajućeg softvera i korišćenjem tabelarnih kalkulatora, ovaj metod postaje izuzetno primenljiv i efikasan u donošenju pravilnih i realnih zaključaka

Cognitive impairment and Alzheimer’s disease: Links with oxidative stress and cholesterol metabolism

Oxidative stress has been implicated in the progression of a number of neurodegenerative diseases, including Alzheimer’s disease (AD), Parkinson’s disease and amyotrophic lateral sclerosis. We carried out an in-depth study of cognitive impairment and its relationships with oxidative stress markers such as ferric-reducing ability of plasma (FRAP), plasma malondialdehyde and total antioxidative capacity (TAC), as well as cholesterol parameters, in two subsets of subjects, AD patients (n = 59) and a control group of neurologically normal subjects (n = 29), attending the University Hospital Salvador in Santiago, Chile. Cognitive impairment was assessed by a set of neuropsychological tests (Mini-Mental State Examination, Boston Naming Test, Ideomotor Praxia by imitation, Semantic Verbal Fluency of animals or words with initial A, Test of Memory Alteration, Frontal Assessment Battery), while the levels of those oxidative stress markers and cholesterol metabolism parameters were determined according with standard bioassays in fresh plasma samples of the two subgroups of patients. No significant differences were observed when the cholesterol parameters (low-, high-density lipoprotein, total cholesterol) of the AD group were compared with normal controls. Interestingly, a correlation was evidenced when the levels of cognitive impairment were analyzed with respect to the plasma antioxidant capacity (AOC) of patients. In this context, the subset of subjects exhibiting cognitive impairment were divided into two subgroups according with their Global Dementia Scale performance: a subgroup with mild AD and a subgroup with moderate to severe AD. Significant differences in AOC were found between subgroups. The different correlations between cognitive impairment of subgroups of subjects with the oxidative stress profile are discussed in the context of AD pathogenesis

Sadržaj i distribucija teških metala u organima i tkivima slatkovodnih riba Zapadne Morave

Uzimajući u obzir da se u vodenoj sredini ribe nalaze na vrhu lanca ishrane, česta je pojava da u svom organizmu akumuliraju određene količine teških metala zbog čega se smatraju jednim od najosetljivijih akvatičnih organizama na prisustvo toksičnih materija. Pošto meso ribe predstavlja jednu od značajnih komponenti ljudske ishrane, prekomerna akumulacija teških metala u muskulaturi riba čini ovu namirnicu zdravstveno nebezbednom za ishranu ljudi. U radu su analizirane koncentracije teških metala kadmijuma (Cd), olova (Pb), žive (Hg) i cinka (Zn) u mišićnom tkivu i jetri bentosnih i omnivormih vrsta riba, uzorkovanih u ekosistemu Zapadna Morava. Cilj rada bio je dobijanje potpunijeg uvida u stepen akumulativnosti ili opterećenosti teškim metalima, kako vode kao ambijenta u kojoj ribe žive, tako i ribljeg mesa kao namirnice. Na osnovu ispitivanja prisustva teških metala u srebrnom karašu (Carassius gibelio) i deverici (Abramis brama) utvrđeno je prisustvo sva četiri analizirana metala, ali u koncentracijama ispod maksimalno dozvoljenih količina (MDK). Na osnovu utvrđenih rezultata može se konstatovati da ekosistem Zapadne Morave pokazuje trend poboljšanja kvaliteta u pogledu opterećenosti antropogenim zagađenjem i da je meso ispitivanih vrsta riba zdravstveno bezbedno i higijenski ispravno za ishranu ljudi. Takođe, relativno niski sadržaji teških metala u jetri riba jasno ukazuju da je u ovom ekosistemu došlo do znatnog sniženja stepena zagađenosti vode i sedimenta u odnosu na ranije periode ispitivanja

Enhanced ZnR/GPR39 activity in breast cancer, an alternative trigger of signaling leading to cell growth

Acquired resistance to the estrogen receptor (ER) antagonist tamoxifen, is a major obstacle in treatment of breast cancer. Changes in Zn2+ accumulation and distribution are associated with tamoxifen-resistance and breast cancer progression. The Zn2+-sensing G-protein coupled receptor, ZnR/GPR39, triggers signaling leading to cell growth, but a role for this receptor in breast cancer in unknown. Using fluorescence imaging, we found Zn2+-dependent Ca2+ release, mediated by ZnR/GPR39 activity, in TAMR tamoxifen-resistant cells derived from MCF-7 cells, but not in ER-expressing MCF-7 or T47D cells. Furthermore, ZnR/GPR39 signaling was monitored in ER negative BT20, MDA-MB-453 and JIMT-1 cells. Expression of ZnR/GPR39 was increased in grade 3 human breast cancer biopsies compared to grade 2. Consistently, analysis of two breast cancer patient cohorts, GDS4057 and TCGA, indicated that in ER-negative tumors higher ZnR/GPR39 mRNA levels are associated with more aggressive tumors. Activation of ZnR/GPR39 in TAMR cells triggered MAPK, mTOR and PI3K signaling. Importantly, enhanced cell growth and invasiveness was observed in the ER negative breast cancer cells, TAMR, MDA-MB-453 and BT20 cells but not in the ER expressing MCF-7 cells. Thus, we suggest ZnR/GPR39 as a potential therapeutic target for combination treatment in breast cancer, particularly relevant in ER negative tumors

Nueva estrategia para el diseño y fabricación de cabezales de fresadora de altas prestaciones

Los cabezales de transmisión mecánica de altas prestaciones son una de las partes más complejas, costosas y problemáticas de una maquina fresadora. Esto es debido a la gran cantidad de canalizaciones para la transmisión de fluidos que deben de contener y a las altas prestaciones mecánicas que se les exigen. En este trabajo se presenta una estrategia para optimizar el diseño y la fabricación de los cuerpos de estos cabezales basada en la incorporación de aleaciones de aluminio y la inclusión de insertos tubulares de acero en la propia fundición que conforma el cabezal. Los insertos tubulares sustituyen a los canales de refrigeración realizados actualmente por taladros de mecanizado y quedan integrados en la masa de aluminio. La nueva metodología ha permitido realizar un diseño que mantiene las prestaciones mecánicas, aumenta la fiabilidad y reduce la masa de estos elementos móviles de fresadoras como ha demostrado la validación experimental de un primer prototipo.High-performance mechanical-transmission heads are one of the most complex, costly and problematic parts of a milling machine, owing to the large amount of piping required for transporting fluids and to the high level of mechanical performance that is required from them. This study proposes a strategy for optimising the design and manufacture of head bodies by using aluminium alloys and by integrating tubular stainless steel inserts in the casting of the head. These tubular inserts that are integrated into the aluminium mass are an alternative to cooling conduits currently made by machine drilling. As demonstrated in the experimental validation of the first prototype, the new method has created a design that retains the same mechanical performance, increases its reliability and reduces the weight of the milling machine’s moving parts.Spanish Ministry of Science and Innovation in the PROFIT Project FIT-020500-2006-50 and by the Agencia de Desarrollo Economico of the Junta de Castilla-Leon (04/06/BU/0008)

Mitochondrial exchanger NCLX plays a major role in the intracellular Ca(2+) signaling, gliotransmission, and proliferation of astrocytes

Mitochondria not only provide cells with energy, but are central to Ca(2+) signaling. Powered by the mitochondrial membrane potential, Ca(2+) enters the mitochondria and is released into the cytosol through a mitochondrial Na(+)/Ca(2+) exchanger. We established that NCLX, a newly discovered mitochondrial Na(+)/Ca(2+) exchanger, is expressed in astrocytes isolated from mice of either sex. Immunoblot analysis of organellar fractions showed that the location of NCLX is confined to mitochondria. Using pericam-based mitochondrial Ca(2+) imaging and NCLX inhibition either by siRNA or by the pharmacological blocker CGP37157, we demonstrated that NCLX is responsible for mitochondrial Ca(2+) extrusion. Suppression of NCLX function altered cytosolic Ca(2+) dynamics in astrocytes and this was mediated by a strong effect of NCLX activity on Ca(2+) influx via store-operated entry. Furthermore, Ca(2+) influx through the store-operated Ca(2+) entry triggered strong, whereas ER Ca(2+) release triggered only modest mitochondrial Ca(2+) transients, indicating that the functional cross talk between the plasma membrane and mitochondrial domains is particularly strong in astrocytes. Finally, silencing of NCLX expression significantly reduced Ca(2+)-dependent processes in astrocytes (i.e., exocytotic glutamate release, in vitro wound closure, and proliferation), whereas Ca(2+) wave propagation was not affected. Therefore, NCLX, by meditating astrocytic mitochondrial Na(+)/Ca(2+) exchange, links between mitochondria and plasma membrane Ca(2+) signaling, thereby modulating cytoplasmic Ca(2+) transients required to control a diverse array of astrocyte functions