Urbaania energiaa. Suvilahden, Hanasaaren A- ja Vuosaaren voimalaitokset osana helsinkiläistä kaupunkiympäristöä

Tutkimus koostuu kolmen Helsingissä sijaitsevan, kolmena eri aikakautena, 1910-, 1950- ja 1990-luvuilla, rakennetun voimalaitoksen arkkitehtuurista ja rakennustyypistä sekä niiden eroista ja erityisyyksistä samoin kuin näiden voimalaitosten roolista ja vaikutuksesta Helsingin kaupunkisuunnitteluun ja -rakentamiseen, kaupunkikuvaan sekä ympäristöestetiikkaan. Tutkimus on rajattu koskemaan erityyppisten voimalaitosten osalta yksinomaan kolmea helsinkiläistä kaupungissa sijaitsevaa voimalaitosta, Suvilahtea, Hanasaari-A:ta ja Vuosaaren A- ja B-laitoksia. Tutkimuksen tarkoituksena on ensinnäkin selvittää sekä periaatteessa että edellä mainittujen kolmen esimerkkikohteen kautta seikkoja, jotka ovat vaikuttaneet kunkin voimalaitoksen arkkitehtuuriin ja rakennustyyppiin kunakin aikakautena. Kaupunkivoimalan olennaiset elementit ovat korkea savupiippu, mittava polttoainevarasto sekä massiiviset rakennusmassat, jotka vaativat runsasta maankäyttöä. Toiseksi tutkimuksessa paneudutaan kaupunkisuunnitteluun laitoksen sijoittumisen osalta sekä ajallisesti että paikallisesti. Kolmanneksi selvitetään kaupunkikuvallisia ja ympäristöesteettisiä seikkoja, sekä niiden vaikutusten kehitystä voimalaitoksen toteutuksen ja nykyhetken kesken. Tutkimuksessa haetaan vastausta kysymykseen, miten Helsingissä sijaitseva voimalaitos arkkitehtuuriltaan, rakennustyypiltään ja sijoitukseltaan on soveltunut ja jatkossa soveltuu kaupunkisuunnittelun kannalta kaupunkikuvallisesti sekä ympäristöesteettisesti kyseiseen kaupunkiympäristöön. Tutkimus selvittää myös sitä ilmeistä ristiriitaa, joka syntyy kaupungin kehittyessä ja laajentuessa, jolloin voimalaitos infrastruktuurinsa ja useimmiten suunnattoman kokonsa vuoksi edustaa pysyvyyttä rakentuvan alueen sisällä. Tässä yhteydessä tutkimuksessa pohditaan esimerkkikohteiden avulla voimalaitoksen säilyttämistä puoltavia rakennustaiteellisia arvoja, mahdollista korvattavuutta, ja siinä yhteydessä haetaan vastauksia jäljelle jäävälle laitosrakennukselle kaupunkisuunnittelun kannalta asetettavista uusiokäytön vaatimuksista ja mahdollisuuksista. Tutkimuksen metodologia on sekä kvantitatiivisesti että kvalitatiivisesti historiallinen, esimerkkikohteita käsiteltäessä tarvittavassa määrin myös mikrohistoriallinen.The study consists of the architecture and building types of three power plants in Helsinki, built in three different eras, in the 1910s, the 1950s and the 1990s, of their differences and special features, as well as of their roles and impacts on urban planning and building, townscape and environmental aesthetics of Helsinki. The study is limited to apply to only three urban power plants out of various types of power plants. These three plants are located in the City of Helsinki: Suvilahti, Hanasaari A, and Vuosaari A and B together. The primary purpose of the study is, in principle and through the above-mentioned three example plants, to clarify matters that have had an impact on the architecture and building type of each power plant in each era, to establish the features typical of the architecture and building type of the time. The essential features of the power plant are the high chimney, wide storage of solid fuel and massive buildings. Secondly, the study focuses on urban planning with respect to the location of the plants in terms of time and place. Thirdly, the study examines townscape and environmentally aesthetic issues and the development of their impact in relation to the implementation of the power plant and the present day. The study also investigates the suitability of the architecture, building type and location of a power plant situated in Helsinki for the particular urban environment in terms of townscape and environmental aesthetics in urban planning. The study also investigates the inevitable con ict that arises when the city develops and expands, in which case the power plant represents stability within the area under construction due to its infrastructure and, in most cases, its huge size. In this context, it will be also debated, using the example locations, the architectural values in support of the conservation and possible replaceability of the power plant. In that connection, the study also looks for answers regarding the requirements and possibilities of reusing the remaining power plant buildings with respect to urban planning. The methodology of the study is historical concerning both quality and quantity. When examining the examples the methodology is also microhistorical.Siirretty Doriast

Brn3c null mutant mice show long-term, incomplete retention of some afferent inner ear innervation

BACKGROUND: Ears of Brn3c null mutants develop immature hair cells, identifiable only by certain molecular markers, and undergo apoptosis in neonates. This partial development of hair cells could lead to enough neurotrophin expression to sustain sensory neurons through embryonic development. We have therefore investigated in these mutants the patterns of innervation and of expression of known neurotrophins. RESULTS: At birth there is a limited expression of BDNF and NT-3 in the mutant sensory epithelia and DiI tracing shows no specific reduction of afferents or efferents that resembles neurotrophin null mutations. At postnatal day 7/8 (P7/8), innervation is severely reduced both qualitatively and quantitatively. 1% of myosin VIIa-positive immature hair cells are present in the mutant cochlea, concentrated in the base. Around 20% of immature hair cells exist in the mutant vestibular sensory epithelia. Despite more severe loss of hair cells (1% compared to 20%), the cochlea retains many more sensory neurons (46% compared to 15%) than vestibular epithelia. Even 6 months old mutant mice have some fibers to all vestibular sensory epithelia and many more to the cochlear apex which lacks MyoVIIa positive hair cells. Topologically organized central cochlea projections exist at least until P8, suggesting that functional hair cells are not required to establish such projections. CONCLUSION: The limited expression of neurotrophins in the cochlea of Brn3c null mice suffices to support many sensory neurons, particularly in the cochlea, until birth. The molecular nature of the long term survival of apical spiral neurons remains unclear

Restrictions in cell cycle progression of adult vestibular supporting cells in response to ectopic cyclin d1 expression

Peer reviewe

Indispensable role of Mdm2/p53 interaction during the embryonic and postnatal inner ear development

p53 is a key component of a signaling network that protects cells against various stresses. As excess p53 is detrimental to cells, its levels are tightly controlled by several mechanisms. The E3 ubiquitin ligase Mdm2 is a major negative regulator of p53. The significance of balanced p53 levels in normal tissues, at different stages of lifetime, is poorly understood. We have studied in vivo how the disruption of Mdm2/p53 interaction affects the early-embryonic otic progenitor cells and their descendants, the auditory supporting cells and hair cells. We found that p53 accumulation, as a consequence of Mdm2 abrogation, is lethal to both proliferative progenitors and non-proliferating, differentiating cells. The sensitivity of postmitotic supporting cells to excess p53 decreases along maturation, suggesting that maturation-related mechanisms limit p53's transcriptional activity towards pro-apoptotic factors. We have also investigated in vitro whether p53 restricts supporting cell's regenerative capacity. Unlike in several other regenerative cellular models, p53 inactivation did not alter supporting cell's proliferative quiescence nor transdifferentiation capacity. Altogether, the postmitotic status of developing hair cells and supporting cells does not confer protection against the detrimental effects of p53 upregulation. These findings might be linked to auditory disturbances observed in developmental syndromes with inappropriate p53 upregulation.Peer reviewe

Fgf9 signaling regulates inner ear morphogenesis through epithelial–mesenchymal interactions

AbstractThe mammalian inner ear comprises the cochleovestibular labyrinth, derived from the ectodermal otic placode, and the encasing bony labyrinth of the temporal bone. Epithelial–mesenchymal interactions are thought to control inner ear development, but the modes and the molecules involved are largely unresolved. We show here that, during the precartilage and cartilage stages, Fgf9 is expressed in specific nonsensory domains of the otic epithelium and its receptors, Fgfr1(IIIc) and Fgfr2(IIIc), widely in the surrounding mesenchyme. To address the role of Fgf9 signaling, we analyzed the inner ears of mice homozygous for Fgf9 null alleles. Fgf9 inactivation leads to a hypoplastic vestibular component of the otic capsule and to the absence of the epithelial semicircular ducts. Reduced proliferation of the prechondrogenic mesenchyme was found to underlie capsular hypoplasticity. Semicircular duct development is blocked at the initial stages, since fusion plates do not form. Our results show that the mesenchyme directs fusion plate formation and they give direct evidence for the existence of reciprocal epithelial–mesenchymal interactions in the developing inner ear. In addition to the vestibule, in the cochlea, Fgf9 mutation caused defects in the interactions between the Reissner's membrane and the mesenchymal cells, leading to a malformed scala vestibuli. Together, these data show that Fgf9 signaling is required for inner ear morphogenesis

Cochlear progenitor number is controlled through mesenchymal FGF receptor signaling

The sensory and supporting cells (SCs) of the organ of Corti are derived from a limited number of progenitors. The mechanisms that regulate the number of sensory progenitors are not known. Here, we show that Fibroblast Growth Factors (FGF) 9 and 20, which are expressed in the non-sensory (Fgf9) and sensory (Fgf20) epithelium during otic development, regulate the number of cochlear progenitors. We further demonstrate that Fgf receptor (Fgfr) 1 signaling within the developing sensory epithelium is required for the differentiation of outer hair cells and SCs, while mesenchymal FGFRs regulate the size of the sensory progenitor population and the overall cochlear length. In addition, ectopic FGFR activation in mesenchyme was sufficient to increase sensory progenitor proliferation and cochlear length. These data define a feedback mechanism, originating from epithelial FGF ligands and mediated through periotic mesenchyme that controls the number of sensory progenitors and the length of the cochlea. DOI: http://dx.doi.org/10.7554/eLife.05921.00

Non-invasive vagus nerve stimulation reduces sympathetic preponderance in patients with tinnitus

Conclusion: Transcutaneous vagal nerve stimulation (tVNS) might offer a targeted, patient-friendly, and low-cost therapeutic tool for tinnitus patients with sympathovagal imbalance. Objectives: Conventionally, VNS has been performed to treat severe epilepsy and depression with an electrode implanted to the cervical trunk of vagus nerve. This study investigated the acute effects of tVNS on autonomic nervous system (ANS) imbalance, which often occurs in patients with tinnitus-triggered stress. Methods: This study retrospectively analysed records of 97 patients who had undergone ANS function testing by heart rate variability (HRV) measurement immediately before and after a 15-60min tVNS stimulation. Results: The pre-treatment HRV recording showed sympathetic preponderance/reduced parasympathetic activity in about three quarters (73%) of patients. Active tVNS significantly increased variability of R-R intervals in 75% of patients and HRV age was decreased in 70% of patients. Either the variability of R-R intervals was increased or the HRV age decreased in 90% of the patients. These results indicate that tVNS can induce a shift in ANS function from sympathetic preponderance towards parasympathetic predominance. tVNS caused no major morbidity, and heart rate monitoring during the tVNS treatment showed no cardiac or circulatory effects (e.g. bradycardia) in any of the patients.Peer reviewe

Cytoskeletal Stability in the Auditory Organ In Vivo : RhoA Is Dispensable for Wound Healing but Essential for Hair Cell Development

Wound healing in the inner ear sensory epithelia is performed by the apical domains of supporting cells (SCs). Junctional F-actin belts of SCs are thin during development but become exceptionally thick during maturation. The functional significance of the thick belts is not fully understood. We have studied the role of F-actin belts during wound healing in the developing and adult cochlea of mice in vivo. We show that the thick belts serve as intracellular scaffolds that preserve the positions of surviving cells in the cochlear sensory epithelium. Junctions associated with the thick F-actin belts did not readily disassemble during wound healing. To compensate for this, basolateral membranes of SCs participated in the closure of surface breach. Because not only neighboring but also distant SCs contributed to wound healing by basolateral protrusions, this event appears to be triggered by contact-independent diffusible signals. In the search for regulators of wound healing, we inactivated RhoA in SCs, which, however, did not limit wound healing. RhoA inactivation in developing outer hair cells (OHCs) caused myosin II delocalization from the perijunctional domain and apical cell-surface enlargement. These abnormalities led to the extrusion of OHCs from the epithelium. These results demonstrate the importance of stability of the apical domain, both in wound repair by SCs and in development of OHCs, and that only this latter function is regulated by RhoA. Because the correct cytoarchitecture of the cochlear sensory epithelium is required for normal hearing, the stability of cell apices should be maintained in regenerative and protective interventions.Peer reviewe

Hearing disorder from music; a neglected dysfunction

Conclusion: Music-induced acute acoustic trauma is not inevitably linked to hearing dysfunction as validated by conventional pure tone audiometry. Tinnitus is often in combination with hyperacusis. Our results point at 'silent hearing loss' as the underlying pathology, having afferent nerve terminal damage rather than hair cell loss as the structural correlate. Objectives: Exposure to loud music is one of the most common causes of acute acoustic trauma, which adolescents and teenagers experience by voluntary exposure to loud music of sound levels up to 110 dB(A). Methods: The clinical and psychophysical data of 104 consecutive patients with music-induced hearing disorder (MIHD) were analyzed to construct individual hearing and tinnitus profiles. In all cases, tinnitus was the presenting symptom. Results: Hearing abilities were normal in about two-thirds of the tinnitus patients. Tinnitus was experienced most often as a high-frequency tone (83%). The Tinnitus Handicap Inventory (THI) scores ranged from 0 to 94 with an average score of 43.1. Visual analog scales (VAS) were used to assess tinnitus loudness (average 42.4) and annoyance (average 54.2), and tinnitus awareness was estimated (average 60.3). All VAS values correlated strongly with the THI. Hyperacusis was present in 65% and 71% of the patients reported sleeping disorders.Peer reviewe