338 research outputs found

    Structure−Function Correlation of Chloroquine and Analogues as Transgene Expression Enhancers in Nonviral Gene Delivery

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    To understand how chloroquine (CQ) enhances transgene expression in polycation-based, nonviral gene delivery systems, a number of CQ analogues with variations in the aliphatic amino side chain or in the aromatic ring are synthesized and investigated. Our studies indicate that the aliphatic amino moiety of CQ is essential to provide increased gene expression. Further, the enhancements are more dramatically affected by changes to the aromatic ring and are positively correlated to the strength of intercalation between DNA and the CQ analogues. Quinacrine (QC), a CQ analogue with a fused acridinyl structure that can strongly intercalate DNA, enhances transfection similarly to CQ at a concentration 10 times lower, while N^4-(4-pyridinyl)-N^1,N^1-diethyl-1,4-pentanediamine (CP), a CQ analogue that has a weakly intercalating pyridinyl ring, shows no effect on gene expression. Subtle change on the 7-substituent of the chloroquine aromatic structure can also greatly affect the ability of the CQ analogues to enhance transgene expression. Transfection in the presence of N^4-(7-trifluoromethyl-4-quinolinyl)-N^1,N^1-diethyl-1,4-pentanediamin e (CQ7a) shows expression efficiency 10 times higher than in the presence of CQ at same concentration, while transfection in the presence of N^4-(4-quinolinyl)-N^1,N^1-diethyl-1,4-pentanediamine (CQ7b) does not reveal any enhancing effects on expression. Through a number of comparative studies with CQ and its analogues, we conclude that there are at least three mechanistic features of CQ that lead to the enhancement in gene expression:  (i) pH buffering in endocytic vesicles, (ii) displacement of polycations from the nucleic acids in polyplexes, and (iii) alteration of the biophysical properties of the released nucleic acid

    Activity-based differentiation of pathologists’ workload in surgical pathology

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    Adequate budget control in pathology practice requires accurate allocation of resources. Any changes in types and numbers of specimens handled or protocols used will directly affect the pathologists’ workload and consequently the allocation of resources. The aim of the present study was to develop a model for measuring the pathologists’ workload that can take into account the changes mentioned above. The diagnostic process was analyzed and broken up into separate activities. The time needed to perform these activities was measured. Based on linear regression analysis, for each activity, the time needed was calculated as a function of the number of slides or blocks involved. The total pathologists’ time required for a range of specimens was calculated based on standard protocols and validated by comparing to actually measured workload. Cutting up, microscopic procedures and dictating turned out to be highly correlated to number of blocks and/or slides per specimen. Calculated workload per type of specimen was significantly correlated to the actually measured workload. Modeling pathologists’ workload based on formulas that calculate workload per type of specimen as a function of the number of blocks and slides provides a basis for a comprehensive, yet flexible, activity-based costing system for pathology

    Dynamic Fluctuation Phenomena in Double Membrane Films

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    Dynamics of double membrane films is investigated in the long-wavelength limit including the overdamped squeezing mode. We demonstrate that thermal fluctuations essentially modify the character of the mode due to its nonlinear coupling to the transversal shear hydrodynamic mode. The corresponding Green function acquires as a function of the frequency a cut along the imaginary semi-axis. Fluctuations lead to increasing the attenuation of the squeezing mode it becomes larger than the `bare' value.Comment: 7 pages, Revte

    Absence of differential predation on rats by Malaysian Barn Owls in oil palm plantations

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    Barn Owls (Tyto alba javanica) have been widely introduced in Malaysian oil palm plantations to control rodent pests. However, their effectiveness in regulating rodent populations is unknown. We investigated whether Barn Owls selected prey with respect to size and sex classes based on data from 128 pellets of Barn Owls compared to 1292 live-trapped rats in an oil palm plantation in Malaysia. The birds mostly fed on Rattus rail as diardii, the most commonly trapped species. Body mass of prey consumed was predicted based on models derived from measurements from trapped rats. Sex of prey was determined by pelvic measurements with reference to those taken from specimens of known gender. There was no clear selection of prey by Barn Owls in relation to size or sex of prey, and no difference in the body mass of prey between the owls' breeding and nonbreeding seasons. The absence of differential predation in Barn Owls may partly explain the lack of dear evidence that they regulate rodent populations and thus act as successful biological control agents

    "Ruvettiin jakamaan maapalloa keskenĂ€mme" : Helsingin Sanomien kehitysmaauutisointi vuosina 1965–1974

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    Tarkastelen tutkielmassani Helsingin Sanomien (HS) kehitysmaauutisointia vuosina 1965–1974. Tavoitteena on selvittÀÀ, miten yhteiskunnan ja journalismin merkittĂ€vĂ€ murroskohta heijastui Suomen suurimman sanomalehden vĂ€littĂ€mÀÀn maailmankuvaan. PÀÀlĂ€hteinĂ€ ovat tekemĂ€ni aikalaistoimittajien haastattelut, PĂ€ivĂ€lehden arkiston teettĂ€mĂ€t toimittajahaastattelut ja muu arkistomateriaali sekĂ€ digitaalisessa muodossa löytyvĂ€t HS:n lehdet vuosilta 1965–1974. Tarkempi analyysi kohdistuu huhti- ja lokakuun lehtiin vuosina 1965, 1968, 1971 ja 1974. Tutkimukseni perusteella HS:n kehitysmaauutisoinnissa tapahtui selkeitĂ€ muutoksia. Vuonna 1965 pÀÀpaino oli kansainvĂ€listen uutistoimistojen sĂ€hkeuutisissa. SĂ€hkeet kattoivat mÀÀrĂ€llisesti suuren joukon maita, mutta aiheiden kĂ€sittely jĂ€i pintapuoliseksi ja nĂ€kökulmat olivat uutistoimistojen valitsemia. Omien toimittajien nimiin kirjattuja juttuja kehitysmaa-aiheista ei vuonna 1965 juuri ollut. Vuonna 1968 tilanne oli samankaltainen. Esimerkiksi maailmalla ja Suomessa suurta huomiota herĂ€ttĂ€nyttĂ€ Biafran kriisiĂ€ ei analysoitu omien toimittajien voimin, eikĂ€ HS lĂ€hettĂ€nyt alueelle omaa toimittajaa. Vuoteen 1971 mennessĂ€ ulkomaantoimituksen omien toimittajien kirjoittamien, kehitysmaita kĂ€sittelevien juttujen mÀÀrĂ€ kasvoi selvĂ€sti. Myös pidempien artikkeleiden mÀÀrĂ€ lisÀÀntyi, samoin tekstien kommentoiva ja kantaaottava tyyli. Vuonna HS:ssa oli jo kolme Euroopan ja Pohjois-Amerikan ulkopuolisia alueita seuraavaa toimittajaa. Vuosina 1971–1974 isoin muutos nĂ€yttĂ€isi tapahtuneen aihepiirien laventumisessa: maailman eriarvoisuuteen ja humanitaarisiin ongelmiin liittyvĂ€t artikkelit lisÀÀntyivĂ€t. Kehitysmaauutisoinnin rinnalle alkoi nousta kehitysmaajournalismi, joka pyrki tuomaan esiin kehityskysymyksiĂ€ ja kehitysmaiden nĂ€kökulmia. Myös kehitysmaita seuraavien toimittajien työmatkat kohdealueilleen lisÀÀntyivĂ€t. Kaikki tutkimukseen haastatellut HS:n ulkomaantoimittajat olivat sitĂ€ mieltĂ€, ettĂ€ uutispÀÀllikkö Olli KivisellĂ€ oli merkittĂ€vĂ€ rooli uudenlaisen uutisoinnin muovaajana. Taustalla vaikutti myös Aatos Erkon vuonna 1965 kĂ€ynnistĂ€mĂ€ muutosprosessi HS:n uudistamiseksi. Erkko halusi huomioida ajan hengen ja avasi ovet nuorelle, usein vasemmistolaiselle, toimittajapolvelle. Tutkimukseni tarkastelujaksolla HS:n kehitysmaita seuraavat toimittajat olivat 1940-luvulla syntyneitĂ€ nuoria miehiĂ€, joilla yliopisto-opinnot olivat juuri takana tai meneillÀÀn. Kaikki olivat aatemaailmaltaan selkeĂ€sti vasemmistolaisia, ja kirjoitusten pontimena oli halu valistaa lukijoita ja vaikuttaa siihen, ettĂ€ imperialistinen maailmanjĂ€rjestys jÀÀ historiaan. Vaikka HS sĂ€ilyi arvoiltaan oikeistoliberaalina, se nĂ€yttÀÀ sallineen “radikaalitoimittajilleen” hyvinkin vasemmistolaisia kannanottoja varsinkin vuosina 1969–1974
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