184 research outputs found
Photoproduction of Long-Lived Holes and Electronic Processes in Intrinsic Electric Fields Seen through Photoinduced Absorption and Dichroism in Ca_3Ga_{2-x}Mn_xGe_3O_{12} Garnets
Long-lived photoinduced absorption and dichroism in the
Ca_3Ga_{2-x}Mn_xGe_3O_{12} garnets with x < 0.06 were examined versus
temperature and pumping intensity. Unusual features of the kinetics of
photoinduced phenomena are indicative of the underlying electronic processes.
The comparison with the case of Ca_3Mn_2Ge_3O_{12}, explored earlier by the
authors, permits one to finally establish the main common mechanisms of
photoinduced absorption and dichroism caused by random electric fields of
photoproduced charges (hole polarons). The rate of their diffusion and
relaxation through recombination is strongly influenced by the same fields,
whose large statistical straggling is responsible for a broad continuous set of
relaxation components (observed in the relaxation time range from 1 to about
1000 min). For Ca_3Ga_{2-x}Mn_xGe_3O_{12}, the time and temperature dependences
of photoinduced absorption and dichroism bear a strong imprint of structure
imperfection increasing with x.Comment: 20 pages, 10 figure
Mid-Quaternary Paleoceanographic Trend in Near-shore Waters of the Northwest Pacific : A Case Study Based on an Offshore Well
An exploratory oil and gas well was drilled on the continental shelf in water 38 m deep at lat. 36°9′33.8″N., long. 140°43′49.3″E., 13 km off the coast of Kashima, Ibaraki Prefecture, Kanto District, Japan. This well sank to the total subbottom depth of 2100 m penetrated sediments ranging back to Late Cretaceous in age. The upper 500 m of well sequence which comprises largely Quaternary sediments was subjected to paleoenvironmental analyses by jointly analyzing microfossils (calcareous nannoplankton and benthic and planktonic foraminifera), mineral content, and oxygen and carbon isotope stratigraphies. Three dated horizons, 0.128, 0.27 and 0.46 Ma, were established by recognizing one marked excursion to negative values in the oxygen isotope record and two calcareous nannoplankton datum levels in the well sequence. A possible hiatus at about 465 m depth terminates this mid-Quaternary sequence which is underlain by late Pliocene strata of about 1.9 Ma and older. Mid-Quaternary paleobathymetric trends were reconstructed for the well site area mainly on the basis of Q-mode cluster analysis of benthic foraminiferal faunas. Deposition of the mid-Quaternary sequence began in the upper bathyal zone and a steady shallowing followed through outer shelf environments to the present-day inner neritic zone. Other paleo-depth indicators such as abundance variations of nannoplankton Florisphaera profuuda and planktonic versus total foraminifera ratios, and variations of ^C isotope record are all supportive of this benthic foraminifera-based depth-trend. Paleotemperature fluctuations were estimated by analyzing oxygen isotope compositions of benthic and planktonic foraminifera and by calculating with the aid of paleoecological transfer functions quantitative estimates of past winter temperatures. The paleotemperature fluctuations estimated for the well site area by these two methods agree well for the lower part of the well sequence, but begin to diverge from the mid-sequence and upwards, probably reflecting increasing effects of local water masses to the oxygen isotope variation. In the Quaternary isotope record of Kashima SK-1 well, no definite interval correlatable with the even-numbered isotope stages was observed. In view of the fact that distinct hiatuses occur in the onshore Quaternary record of Kanto District located to the west of the well site, the lack of even-numbered isotope stages is interpreted to signify periods of greatly reduced sedimentation or possibly non-deposition in a broad coastal region encompassing also the continental shelf around the well site. Mid-Quaternary paleoceanography around the well site prior to about 0.35 Ma was under the general influence of cold Oyashio Current with its strength varying greatly from time to time, whereas the latter time period responding to the diminishing Oyashio Current saw a seesaw game of two warm currents, Kuroshio and Tsugaru, expanding and retreating alternatively over a broad region of the sea off Northeast Honshu, Japan
Intestinal Parasitic Infections of School Children in Kwale District of Coast Province, Kenya
The study was carried out to determine the geographical distribution of intestinal parasitic infection in Kwale district, Kenya in 1981. Stool specimens were obtained from the school children and were examined for the presence of both helminth ova and protozoan cysts. Entamoeba coli, Ascaris lumbricoides, hookworm and Trichuris trichiura were found to be common in the area. The prevalence of ascariasis and trichuriasis showed similar geographical distribution among divisions. The prevalence were high in both Central and Southhern but relatively low in Kinango and Kubo divisions. However, the geographical distribution of prevalence of E. coli and hookworm infections were different from those of ascariasis and trichuriasis. These results might reflect the differences of the population densities, the water sources and the sanitary conditions
FABP7 expression in normal and stab-injured brain cortex and its role in astrocyte proliferation
Reactive gliosis, in which astrocytes as well as other types of glial cells undergo massive proliferation, is a common hallmark of all brain pathologies. Brain-type fatty acid-binding protein (FABP7) is abundantly expressed in neural stem cells and astrocytes of developing brain, suggesting its role in differentiation and/or proliferation of glial cells through regulation of lipid metabolism and/or signaling. However, the role of FABP7 in proliferation of glial cells during reactive gliosis is unknown. In this study, we examined the expression of FABP7 in mouse cortical stab injury model and also the phenotype of FABP7-KO mice in glial cell proliferation. Western blotting showed that FABP7 expression was increased significantly in the injured cortex compared with the contralateral side. By immunohistochemistry, FABP7 was localized to GFAP+ astrocytes (21% of FABP7+ cells) and NG2+ oligodendrocyte progenitor cells (62%) in the normal cortex. In the injured cortex there was no change in the population of FABP7+/NG2+ cells, while there was a significant increase in FABP7+/GFAP+ cells. In the stab-injured cortex of FABP7-KO mice there was decrease in the total number of reactive astrocytes and in the number of BrdU+ astrocytes compared with wild-type mice. Primary cultured astrocytes from FABP7-KO mice also showed a significant decrease in proliferation and omega-3 fatty acid incorporation compared with wild-type astrocytes. Overall, these data suggest that FABP7 is involved in the proliferation of astrocytes by controlling cellular fatty acid homeostasis
Antineoplastic effects of rosiglitazone and PPARγ transactivation in neuroblastoma cells
Neuroblastoma (NB) is the most common extracranial solid tumour in infants. Unfortunately, most children present with advanced disease and have a poor prognosis. In the present study, we evaluated the role of the peroxisome proliferator-activated receptor γ (PPARγ) agonist rosiglitazone (RGZ) in two NB cell lines (SK-N-AS and SH-SY5Y), which express PPARγ. Rosiglitazone decreased cell proliferation and viability to a greater extent in SK-N-AS than in SH-SY5Y. Furthermore, 20 μM RGZ significantly inhibited cell adhesion, invasiveness and apoptosis in SK-N-AS, but not in SH-SY5Y. Because of the different response of SK-N-AS and SH-SY5Y cells to RGZ, the function of PPARγ as a transcriptional activator was assessed. Noticeably, transient transcription experiments with a PPARγ responsive element showed that RGZ induced a three-fold increase of the reporter activity in SK-N-AS, whereas no effect was observed in SH-SY5Y. The different PPARγ activity may be likely due to the markedly lower amount of phopshorylated (i.e. inactive) protein observed in SK-N-AS. To our knowledge, this is the first demonstration that the differential response of NB cells to RGZ may be related to differences in PPARγ transactivation. This finding indicates that PPARγ activity may be useful to select those patients, for whom PPARγ agonists may have a beneficial therapeutic effect
Impact of primary kidney disease on the effects of empagliflozin in patients with chronic kidney disease: secondary analyses of the EMPA-KIDNEY trial
Background: The EMPA KIDNEY trial showed that empagliflozin reduced the risk of the primary composite outcome of kidney disease progression or cardiovascular death in patients with chronic kidney disease mainly through slowing progression. We aimed to assess how effects of empagliflozin might differ by primary kidney disease across its broad population. Methods: EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA). Patients were eligible if their estimated glomerular filtration rate (eGFR) was 20 to less than 45 mL/min per 1·73 m2, or 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher at screening. They were randomly assigned (1:1) to 10 mg oral empagliflozin once daily or matching placebo. Effects on kidney disease progression (defined as a sustained ≥40% eGFR decline from randomisation, end-stage kidney disease, a sustained eGFR below 10 mL/min per 1·73 m2, or death from kidney failure) were assessed using prespecified Cox models, and eGFR slope analyses used shared parameter models. Subgroup comparisons were performed by including relevant interaction terms in models. EMPA-KIDNEY is registered with ClinicalTrials.gov, NCT03594110. Findings: Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and followed up for a median of 2·0 years (IQR 1·5–2·4). Prespecified subgroupings by primary kidney disease included 2057 (31·1%) participants with diabetic kidney disease, 1669 (25·3%) with glomerular disease, 1445 (21·9%) with hypertensive or renovascular disease, and 1438 (21·8%) with other or unknown causes. Kidney disease progression occurred in 384 (11·6%) of 3304 patients in the empagliflozin group and 504 (15·2%) of 3305 patients in the placebo group (hazard ratio 0·71 [95% CI 0·62–0·81]), with no evidence that the relative effect size varied significantly by primary kidney disease (pheterogeneity=0·62). The between-group difference in chronic eGFR slopes (ie, from 2 months to final follow-up) was 1·37 mL/min per 1·73 m2 per year (95% CI 1·16–1·59), representing a 50% (42–58) reduction in the rate of chronic eGFR decline. This relative effect of empagliflozin on chronic eGFR slope was similar in analyses by different primary kidney diseases, including in explorations by type of glomerular disease and diabetes (p values for heterogeneity all >0·1). Interpretation: In a broad range of patients with chronic kidney disease at risk of progression, including a wide range of non-diabetic causes of chronic kidney disease, empagliflozin reduced risk of kidney disease progression. Relative effect sizes were broadly similar irrespective of the cause of primary kidney disease, suggesting that SGLT2 inhibitors should be part of a standard of care to minimise risk of kidney failure in chronic kidney disease. Funding: Boehringer Ingelheim, Eli Lilly, and UK Medical Research Council
Decolonial Feminism as Reflexive Praxis: Lugones\u27s World -Travelling as Stories of Friendship in Academia
This essay demonstrates a methodology for engaging in María Lugones\u27s world -travelling: reflexive storytelling in building Women of Color friendships. Beginning with Lugones\u27s articulation of world -travelling, the authors use vignettes from their own friendships in academia to reflect on how world -travelling intersects with decolonial feminism in theory and practice. Taking inspiration from the stories of Women of Color, which Lugones herself includes in her work, the authors juxtapose Lugones\u27s words with experiential vignettes. Beginning with reflections and meanings of home, the authors forward a reflexive method of analysis through the form of writing. In analyzing world -travelling through playfulness, hanging out, invitation, teasing, and its opposite, agonistic play, the authors build new understandings of how to approach travel and knowledge production. Bridging the social sciences and humanities, the authors\u27 collective writing also suggests friendship as a pathway to decolonial feminist coalition building in academia, a world that has historically been alienating to Women of Color
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