1,934 research outputs found
Household air pollution from solid fuel use as a dose-dependent risk factor for cognitive impairment in northern China
The relationship between exposure to household air pollution (HAP) from solid fuel use and cognition remains poorly understood. Among 401 older adults in peri-urban northern China enrolled in the INTERMAP-China Prospective Study, we estimated the associations between exposure to HAP and z-standardized domain-specific and overall cognitive scores from the Montreal Cognitive Assessment. Interquartile range increases in exposures to fine particulate matter (53.2-µg/m3) and black carbon (0.9-µg/m3) were linearly associated with lower overall cognition [- 0.13 (95% confidence interval: - 0.22, - 0.04) and - 0.10 (- 0.19, - 0.01), respectively]. Using solid fuel indoors and greater intensity of its use were also associated with lower overall cognition (range of point estimates: - 0.13 to - 0.03), though confidence intervals included zero. Among individual cognitive domains, attention had the largest associations with most exposure measures. Our findings indicate that exposure to HAP may be a dose-dependent risk factor for cognitive impairment. As exposure to HAP remains pervasive in China and worldwide, reducing exposure through the promotion of less-polluting stoves and fuels may be a population-wide intervention strategy to lessen the burden of cognitive impairment
Basonuclin-Null Mutation Impairs Homeostasis and Wound Repair in Mouse Corneal Epithelium
At least two cellular processes are required for corneal epithelium homeostasis and wound repair: cell proliferation and cell-cell adhesion. These processes are delicately balanced to ensure the maintenance of normal epithelial function. During wound healing, these processes must be reprogrammed in coordination to achieve a rapid re-epithelialization. Basonuclin (Bnc1) is a cell-type-specific transcription factor expressed mainly in the proliferative keratinocytes of stratified epithelium (e.g., corneal epithelium, epidermis and esophageal epithelium) and the gametogenic cells in testis and ovary. Our previous work suggested that basonuclin could regulate transcription of ribosomal RNA genes (rDNA) and genes involved in chromatin structure, transcription regulation, cell-cell junction/communication, ion-channels and intracelllular transportation. However, basonuclin's role in keratinocytes has not been demonstrated in vivo. Here we show that basonuclin-null mutation disrupts corneal epithelium homeostasis and delays wound healing by impairing cell proliferation. In basonuclin-null cornea epithelium, RNA polymerase I (Pol I) transcription is perturbed. This perturbation is unique because it affects transcripts from a subset of rDNA. Basonuclin-null mutation also perturbs RNA polymerase II (Pol II) transcripts from genes encoding chromatin structure proteins histone 3 and HMG2, transcription factor Gli2, gap-junction protein connexin 43 and adheren E-cadherin. In most cases, a concerted change in mRNA and protein level is observed. However, for E-cadherin, despite a notable increase in its mRNA level, its protein level was reduced. In conclusion, our study establishes basonuclin as a regulator of corneal epithelium homeostasis and maintenance. Basonuclin likely coordinates functions of a subset of ribosomal RNA genes (rDNA) and a group of protein coding genes in cellular processes critical for the regulation of cell proliferation
Improved change detection with nearby hands
Recent studies have suggested altered visual processing for objects that are near the hands. We present three experiments that test whether an observer’s hands near the display facilitate change detection. While performing the task, observers placed both hands either near or away from the display. When their hands were near the display, change detection performance was more accurate and they held more items in visual short-term memory (experiment 1). Performance was equally improved for all regions across the entire display, suggesting a stronger attentional engagement over all visual stimuli regardless of their relative distances from the hands (experiment 2). Interestingly, when only one hand was placed near the display, we found no facilitation from the left hand and a weak facilitation from the right hand (experiment 3). Together, these data suggest that the right hand is the main source of facilitation, and both hands together produce a nonlinear boost in performance (superadditivity) that cannot be explained by either hand alone. In addition, the presence of the right hand biased observers to attend to the right hemifield first, resulting in a right-bias in change detection performance (experiments 2 and 3)
Meconium pseudocyst secondary to ileum volvulus perforation without peritoneal calcification: a case report
<p>Abstract</p> <p>Introduction</p> <p>A case of giant meconium pseudocyst secondary to ileum volvulus perforation is presented. Conventional radiographic features of meconium peritonitis with secondary meconium pseudocyst formation are well described. Our case is unusual in comparison to other cases reported in the literature and needs to be reported because the meconium pseudocyst presented without the typical ultrasound features (calcifications, polyhydramnios and ascites) and was initially identified as an abdominal mass.</p> <p>Case presentation</p> <p>We describe the case of a 29-year-old Caucasian woman in her third trimester of pregnancy, in which an abdominal mass was detected in the fetus. The newborn was diagnosed in the early neonatal period with meconium pseudocyst secondary to ileum volvulus perforation.</p> <p>Conclusions</p> <p>The prenatal appearance of a meconium pseudocyst can be complemented by other signs of bowel obstruction (if present) such as polyhydramnios and fetal bowel dilatation. This is an original case report of interest to all clinicians in the perinatology and fetal ultrasound field. We consider that the utility of this case is the recognition that a meconium pseudocyst might appear without the typical ultrasound features and should be considered as a differential diagnosis when an echogenic intra-abdominal cyst is seen.</p
Phytoplankton dynamics in relation to seasonal variability and upwelling and relaxation patterns at the mouth of Ria de Aveiro (West Iberian Margin) over a four-year period
From June 2004 to December 2007, samples were weekly collected at a fixed station located at the mouth of Ria de Aveiro (West Iberian Margin). We examined the seasonal and inter-annual fluctuations in composition and community structure of the phytoplankton in relation to the main environmental drivers and assessed the influence of the oceano-graphic regime, namely changes in frequency and intensity of upwelling events, over the dynamics of the phytoplankton assemblage. The samples were consistently handled and a final subset of 136 OTUs (taxa with relative abundance > 0.01%) was subsequently submitted to various multivariate analyses. The phytoplankton assemblage showed significant changes at all temporal scales but with an overriding importance of seasonality over longer-(inter-annual) or shorter-term fluctuations (upwelling-related). Sea-surface temperature, salinity and maximum upwelling index were retrieved as the main driver of seasonal change. Seasonal signal was most evident in the fluctuations of chlorophyll a concentration and in the high turnover from the winter to spring phytoplankton assemblage. The seasonal cycle of production and succession was disturbed by upwelling events known to disrupt thermal stratification and induce changes in the phytoplankton assemblage. Our results indicate that both the frequency and intensity of physical forcing were important drivers of such variability, but the outcome in terms of species composition was highly dependent on the available local pool of species and the timing of those events in relation to the seasonal cycle. We conclude that duration, frequency and intensity of upwelling events, which vary seasonally and inter-annually, are paramount for maintaining long-term phytoplankton diversity likely by allowing unstable coexistence and incorporating species turnover at different scales. Our results contribute to the understanding of the complex mechanisms of coastal phytoplankton dynamics in relation to changing physical forcing which is fundamental to improve predictability of future prospects under climate change.Portuguese Foundation for Science and Technology (FCT, Portugal) [SFRH/BPD/ 94562/2013]; FEDER funds; national funds; CESAM [UID/AMB/50017]; FCT/MEC through national funds; FEDERinfo:eu-repo/semantics/publishedVersio
New insights into ion regulation of cephalopod molluscs: a role of epidermal ionocytes in acid-base regulation during embryogenesis
The constraints of an active life in a pelagic habitat led to numerous convergent morphological and physiological adaptations that enable cephalopod molluscs and teleost fishes to compete for similar resources. Here we show for the first time that such convergent developments are also found in the ontogenetic progression of ion regulatory tissues: as in teleost fish epidermal ionocytes scattered on skin and yolk sac of cephalopod embryos appear to be responsible for ionic and acid-base regulation before gill epithelia become functional. Ion and acid-base regulation is crucial in cephalopod embryos, as they are surrounded by a hypercapnic egg fluid with a pCO2 of 0.2-0.4 kPa. Epidermal ionocytes were characterized via immunohistochemistry, in situ hybridization and vital dye staining techniques. We found one group of cells that is recognized by Concavalin A and MitoTracker, which also expresses Na+/H+ exchangers (NHE) and Na+/K+-ATPase. Similar to findings obtained in teleosts these NHE3-rich cells take up sodium in exchange for protons, illustrating the energetic superiority of NHE based proton excretion in marine systems. In vivo electrophysiological techniques demonstrated that acid equivalents are secreted by the yolk and skin integument. Intriguingly, epidermal ionocytes of cephalopod embryos are ciliated as demonstrated by scanning electron microscopy suggesting a dual function of epithelial cells in water convection and ion regulation. These findings add significant knowledge to our mechanistic understanding of hypercapnia tolerance in marine organisms, as it demonstrates that marine taxa which were identified as powerful acid-base regulators during hypercapnic challenges already exhibit strong acid-base regulatory abilities during embryogenesis
Linking Hydrothermal Geochemistry to Organismal Physiology: Physiological Versatility in Riftia pachyptila from Sedimented and Basalt-hosted Vents
Much of what is known regarding Riftia pachyptila physiology is based on the wealth of studies of tubeworms living at diffuse flows along the fast-spreading, basalt-hosted East Pacific Rise (EPR). These studies have collectively suggested that Riftia pachyptila and its chemoautotrophic symbionts are physiologically specialized, highly productive associations relying on hydrogen sulfide and oxygen to generate energy for carbon fixation, and the symbiont's nitrate reduction to ammonia for energy and biosynthesis. However, Riftia also flourish in sediment-hosted vents, which are markedly different in geochemistry than basalt-hosted systems. Here we present data from shipboard physiological studies and global quantitative proteomic analyses of Riftia pachyptila trophosome tissue recovered from tubeworms residing in the EPR and the Guaymas basin, a sedimented, hydrothermal vent field. We observed marked differences in symbiont nitrogen metabolism in both the respirometric and proteomic data. The proteomic data further suggest that Riftia associations in Guaymas may utilize different sulfur compounds for energy generation, may have an increased capacity for energy storage, and may play a role in degrading exogenous organic carbon. Together these data reveal that Riftia symbionts are far more physiologically plastic than previously considered, and that -contrary to previous assertions- Riftia do assimilate reduced nitrogen in some habitats. These observations raise new hypotheses regarding adaptations to the geochemical diversity of habitats occupied by Riftia, and the degree to which the environment influences symbiont physiology and evolution
Do breast implants after a mastectomy affect subsequent prognosis and survival?
In a large study, published in this issue of Breast Cancer Research, Le and colleagues report that women receiving implants after mastectomies for early-stage breast cancer experience lower breast cancer mortality than women not receiving implants. Assessment of survival patterns among women receiving reconstructive implants is complex given unique patient characteristics, disease attributes, and treatment patterns. The interpretation of reduced mortality from breast cancer must be assessed in light of significantly reduced risks of death from most other causes. In contrast, patients receiving post-mastectomy implants had elevated rates of suicide, consistent with findings among women with cosmetic implants. Additional well-designed investigations are needed to clarify survival patterns among women receiving reconstructive implants
Gadolinium oxide nanocrystal nonvolatile memory with HfO2/Al2O3 nanostructure tunneling layers
In this study, Gd2O3 nanocrystal (Gd2O3-NC) memories with nanostructure tunneling layers are fabricated to examine their performance. A higher programming speed for Gd2O3-NC memories with nanostructure tunneling layers is obtained when compared with that of memories using a single tunneling layer. A longer data retention (< 15% charge loss after 104 s) is also observed. This is due to the increased physical thickness of the nanostructure tunneling layer. The activation energy of charge loss at different temperatures is estimated. The higher activation energy value (0.13 to 0.17 eV) observed at the initial charge loss stage is attributed to the thermionic emission mechanism, while the lower one (0.07 to 0.08 eV) observed at the later charge loss stage is attributed to the direct tunneling mechanism. Gd2O3-NC memories with nanostructure tunneling layers can be operated without degradation over several operation cycles. Such NC structures could potentially be used in future nonvolatile memory applications
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