265 research outputs found

    Studies on Gene Expression and Developmental Competence of Bovine Embryos Produced Under Different Conditions of Heat Stress

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    Gene expression is required in all steps of embryonic development and therefore heat stress is known to reduce developmental competence after direct exposure of oocytes and embryos to different conditions of heat shock, by decreasing protein synthesis. Moreover, as in somatic cells, the heat stress befuddles the integration of RNA and posttranscriptional modification of RNA, the assumption was that during meiotic maturation heat shock may mutate RNA within oocytes, with the possibility of altering the surrounding cumulus cells, causing, thus, reductions in development. Heat shock proteins (HSP) are among the first proteins produced during embryonic development and are crucial to cell function. The HSP70 (HSPA14 gene) is an important part of the cell’s machinery for folding, unfolding, transport, localization of proteins and differentiation, regulation of the embryonic cell cycle and helping to protect cells from stress. Therefore, HSPA14 is an apoptotic gene induced by heat shock is associated with embryonic loss, playing an important role of control mechanism of processes involved in growth, cellular differentiation, and embryonic development. In addition the connexin proteins (e.g. Cx43), related to gap junctions, are expressed in numerous tissues including gonads, act as a mediator of heat stress effect on cells. In the present review, the effect of heat stress on bovine embryonic development in a physiologic and genetic point of view is fully discussed

    Experimental Study and Optimization of Machining Parameters in Turning of AISI 1040 Steel with Micro-grooved WC Cutting Tools

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    In dry turning, control over chip formation and the need for the automated machining lead to an advancement in cutting tools. Such concern towards chip breakability is necessary in reducing tool wear, tool tip temperatures and surface roughness of workpiece material. The present study proposes a new development in the traditionally available cutting tools, which acts like a chip breaker. A series of micro-grooves are machined on the rake face of Tungsten carbide (WC) cutting tools using sinker Electric Discharge Machine (EDM). These micro-grooved tools are used to dissolve long continuous chips and heat from the cutting zone in the dry machining of AISI 1040 steel. The results of micro-grooved cutting tools have shown improvement in reducing the tool tip temperatures and surface roughness compared to the conventional cutting tools. The consolidated chip flow phenomenon of plain WC tools is used to decide the location of micro-grooves on the tool rake face. A Taguchi orthogonal array is used to design an experimental layout with minimum number of repetitions in the experiments. Signal-to-noise  ratios and ANOVA is used to understand and identify the significant factors & their level among the input variables on responses.From the results, it is identified that the cutting speed is the most influencing parameter for tool tip temperature at level 1 (i.e. 112 m/min) and surface roughness at level 5 (i.e. 720 m/min)

    Does native Trypanosoma cruzi calreticulin mediate growth inhibition of a mammary tumor during infection?

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    Indexación: Web of Science.Background: For several decades now an antagonism between Trypanosoma cruzi infection and tumor development has been detected. The molecular basis of this phenomenon remained basically unknown until our proposal that T. cruzi Calreticulin (TcCRT), an endoplasmic reticulum-resident chaperone, translocated-externalized by the parasite, may mediate at least an important part of this effect. Thus, recombinant TcCRT (rTcCRT) has important in vivo antiangiogenic and antitumor activities. However, the relevant question whether the in vivo antitumor effect of T. cruzi infection is indeed mediated by the native chaperone (nTcCRT), remains open. Herein, by using specific modified anti-rTcCRT antibodies (Abs), we have neutralized the antitumor activity of T. cruzi infection and extracts thereof, thus identifying nTcCRT as a valid mediator of this effect. Methods: Polyclonal anti-rTcCRT F(ab')(2) Ab fragments were used to reverse the capacity of rTcCRT to inhibit EAhy926 endothelial cell (EC) proliferation, as detected by BrdU uptake. Using these F(ab')(2) fragments, we also challenged the capacity of nTcCRT, during T. cruzi infection, to inhibit the growth of an aggressive mammary adenocarcinoma cell line (TA3-MTXR) in mice. Moreover, we determined the capacity of anti-rTcCRT Abs to reverse the antitumor effect of an epimastigote extract (EE). Finally, the effects of these treatments on tumor histology were evaluated. Results: The rTcCRT capacity to inhibit ECs proliferation was reversed by anti-rTcCRT F(ab')(2) Ab fragments, thus defining them as valid probes to interfere in vivo with this important TcCRT function. Consequently, during infection, these Ab fragments also reversed the in vivo experimental mammary tumor growth. Moreover, anti-rTcCRT Abs also neutralized the antitumor effect of an EE, again identifying the chaperone protein as an important mediator of this anti mammary tumor effect. Finally, as determined by conventional histological parameters, in infected animals and in those treated with EE, less invasive tumors were observed while, as expected, treatment with F(ab')(2) Ab fragments increased malignancy. Conclusion: We have identified translocated/externalized nTcCRT as responsible for at least an important part of the anti mammary tumor effect of the chaperone observed during experimental infections with T. cruzi.http://bmccancer.biomedcentral.com/articles/10.1186/s12885-016-2764-

    Owning an overweight or underweight body: distinguishing the physical, experienced and virtual body

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    Our bodies are the most intimately familiar objects we encounter in our perceptual environment. Virtual reality provides a unique method to allow us to experience having a very different body from our own, thereby providing a valuable method to explore the plasticity of body representation. In this paper, we show that women can experience ownership over a whole virtual body that is considerably smaller or larger than their physical body. In order to gain a better understanding of the mechanisms underlying body ownership, we use an embodiment questionnaire, and introduce two new behavioral response measures: an affordance estimation task (indirect measure of body size) and a body size estimation task (direct measure of body size). Interestingly, after viewing the virtual body from first person perspective, both the affordance and the body size estimation tasks indicate a change in the perception of the size of the participant’s experienced body. The change is biased by the size of the virtual body (overweight or underweight). Another novel aspect of our study is that we distinguish between the physical, experienced and virtual bodies, by asking participants to provide affordance and body size estimations for each of the three bodies separately. This methodological point is important for virtual reality experiments investigating body ownership of a virtual body, because it offers a better understanding of which cues (e.g. visual, proprioceptive, memory, or a combination thereof) influence body perception, and whether the impact of these cues can vary between different setups

    53BP1 Enforces Distinct Pre- and Post-resection Blocks on Homologous Recombination.

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    53BP1 activity drives genome instability and lethality in BRCA1-deficient mice by inhibiting homologous recombination (HR). The anti-recombinogenic functions of 53BP1 require phosphorylation-dependent interactions with PTIP and RIF1/shieldin effector complexes. While RIF1/shieldin blocks 5'-3' nucleolytic processing of DNA ends, it remains unclear how PTIP antagonizes HR. Here, we show that mutation of the PTIP interaction site in 53BP1 (S25A) allows sufficient DNA2-dependent end resection to rescue the lethality of BRCA1Δ11 mice, despite increasing RIF1 "end-blocking" at DNA damage sites. However, double-mutant cells fail to complete HR, as excessive shieldin activity also inhibits RNF168-mediated loading of PALB2/RAD51. As a result, BRCA1Δ1153BP1S25A mice exhibit hallmark features of HR insufficiency, including premature aging and hypersensitivity to PARPi. Disruption of shieldin or forced targeting of PALB2 to ssDNA in BRCA1D1153BP1S25A cells restores RNF168 recruitment, RAD51 nucleofilament formation, and PARPi resistance. Our study therefore reveals a critical function of shieldin post-resection that limits the loading of RAD51.We thank Anthony Tubbs for comments on the paper; Jennifer Mehalko and Dom Esposito (Protein Expression Laboratory, Frederick National Laboratory for Cancer Research) for transgenic constructs; Karim Baktiar, Diana Haines, and Elijah Edmonson (Pathology/Histotechnology Laboratory, Frederick National Laboratory for Cancer Research) for rodent necropsy, pathology analysis, and imaging; Joseph Kalen and Nimit Patel (Small Animal Imaging Program, Frederick National Laboratory for Cancer Research) for X-ray computed tomography (CT) scan imaging; Jennifer Wise and Kelly Smith for assistance with animal work; Davide Robbiani and Kai Ge for antibodies; Dan Durocher for shieldin constructs; David Goldstein and the CCR Genomics core for sequencing support; and Neil Johnson for discussions. Research in the J.M.S. laboratory is supported by NIH grant R01CA197506. Research in the N.M. laboratory is supported by NIH grant R01 227001. The A.N. laboratory is supported by the Intramural Research Program of the NIH, an Ellison Medical Foundation Senior Scholar in Aging Award (AG-SS-2633-11), the Department of Defense Idea Expansion (W81XWH-15-2-006) and Breakthrough (W81XWH-16-1-599) Awards, the Alex's Lemonade Stand Foundation Award, and an NIH Intramural FLEX Award.S

    Severidade da mancha foliar de diplodia (Stenocarpella macrospora) e sua relação com a incidência do patógeno e a germinação, em grãos de híbridos comerciais e experimentais de milho (Zea mays L.).

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    O fungo Stenocarpella macrospora (Sin. Diplodia macrospora) é um dos patógenos associados ao complexo de podridões de colmo e espiga e, em híbridos suscetíveis, pode causar também grandes lesões foliares. O objetivo deste trabalho foi avaliar a severidade do fungo via mancha foliar (Stenocarpella macrospora) e a sua relação com a incidência do patógeno em grãos de milho, bem como avaliar o efeito dessa incidência sobre a germinação de grãos de diferentes híbridos de milho. Para tanto, foram instalados experimentos com híbridos comerciais e experimentais em dois anos consecutivos (2002/2003 e 2003/2004), no campo experimental da Dow AgroSciences, no município de Uberaba (MG)

    Categorising interventions to levels of inpatient care for small and sick newborns: Findings from a global survey.

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    BACKGROUND: In 2017, 2.5 million newborns died, mainly from prematurity, infections, and intrapartum events. Preventing these deaths requires health systems to provide routine and emergency care at birth, and quality inpatient care for small and sick newborns. Defined levels of emergency obstetric care (EmOC) and standardised measurement of "signal functions" has improved tracking of maternal care in low- and middle-income countries (LMICs). Levels of newborn care, particularly for small and sick newborns, and associated signal functions are still not consistently defined or tracked. METHODS: Between November 2016-November 2017, we conducted an online survey of professionals working in maternal and newborn health. We asked respondents to categorise 18 clinical care interventions that could act as potential signal functions for small and sick newborns to 3 levels of care they thought were appropriate for health systems in LMICs to provide: "routine care at birth", "special care" and "intensive care". We calculated the percentage of respondents that classified each intervention at each level of care and stratified responses to look at variation by respondent characteristics. RESULTS: Six interventions were classified to specific levels by more than 50% of respondents as "routine care at birth," three interventions as "special care" and one as "intensive care". Eight interventions were borderline between these care levels. Responses were more consistent for interventions with relevant WHO clinical care guidelines while more variation in respondents' classification was observed in complex interventions that lack standards or guidelines. Respondents with experience in lower-income settings were more likely to assign a higher level of care for more complex interventions. CONCLUSIONS: Results were consistent with known challenges of scaling up inpatient care in lower-income settings and underline the importance of comprehensive guidelines and standards for inpatient care. Further work is needed to develop a shortlist of newborn signal functions aligned with emergency obstetric care levels to track universal health coverage for mothers and their newborns

    Processing of indexical information requires time: Evidence from change deafness

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    Studies of change detection have increased our understanding of attention, perception, and memory. In two innovative experiments we showed that the change detection phenomenon can be used to examine other areas of cognition—specifically, the processing of linguistic and indexical information in spoken words. One hypothesis suggests that cognitive resources must be used to process indexical information, whereas an alternative suggests that it is processed more slowly than linguistic information. Participants performed a lexical decision task and were asked whether the voice presenting the stimuli changed. Nonwords varying in their likeness to real words were used in the lexical decision task to encourage participants to vary the amount of cognitive resources/processing time. More cognitive resources/processing time are required to make a lexical decision with word-like nonwords. Participants who heard word-like nonwords were more likely to detect the change when it occurred (Experiment 1) and were more confident that the voice was the same when it did not change (Experiment 2). These results suggest that indexical information is processed more slowly than linguistic information and demonstrate how change detection can provide insight to other areas of cognition

    Changes in Early Cortical Visual Processing Predict Enhanced Reactivity in Deaf Individuals

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    Individuals with profound deafness rely critically on vision to interact with their environment. Improvement of visual performance as a consequence of auditory deprivation is assumed to result from cross-modal changes occurring in late stages of visual processing. Here we measured reaction times and event-related potentials (ERPs) in profoundly deaf adults and hearing controls during a speeded visual detection task, to assess to what extent the enhanced reactivity of deaf individuals could reflect plastic changes in the early cortical processing of the stimulus. We found that deaf subjects were faster than hearing controls at detecting the visual targets, regardless of their location in the visual field (peripheral or peri-foveal). This behavioural facilitation was associated with ERP changes starting from the first detectable response in the striate cortex (C1 component) at about 80 ms after stimulus onset, and in the P1 complex (100–150 ms). In addition, we found that P1 peak amplitudes predicted the response times in deaf subjects, whereas in hearing individuals visual reactivity and ERP amplitudes correlated only at later stages of processing. These findings show that long-term auditory deprivation can profoundly alter visual processing from the earliest cortical stages. Furthermore, our results provide the first evidence of a co-variation between modified brain activity (cortical plasticity) and behavioural enhancement in this sensory-deprived population

    Attention in neglect and extinction: Assessing the degree of correspondence between visual and auditory impairments using matched tasks

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    Claims have been made for associated degrees of impairment on both visual and auditory performance in unilateral neglect and extinction. Since this evidence is primarily based on different tests in each modality, it is difficult to properly quantify the degree of association between performance in vision and audition. The current study compares visual and auditory extinction and temporal order judgments (TOJs) in two cases with clinical visual neglect. Stimuli in both modalities were precisely matched in their temporal and spatial parameters. The results reveal a mixed pattern of association between different auditory tests and their visual counterparts. This suggests that associations between visual and auditory neglect can occur but these are neither obligatory nor pervasive. Instead, our data support models of spatial impairment in neglect and extinction that acknowledge differences in the contribution of spatial information to performance in each modality in responses to changing task demands
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