Interactions of a collapsing laser-induced cavitation bubble with a hemispherical droplet attached to a rigid boundary

We investigate experimentally and theoretically the interactions between a cavitation bubble and a hemispherical pendant oil droplet immersed in water. In experiments, the cavitation bubble is generated by a focused laser pulse right below the pendant droplet with well-controlled bubble-wall distances and bubble-droplet size ratios. By high-speed imaging, four typical interactions are observed, namely, oil droplet rupture, water droplet entrapment, oil droplet large deformation, and oil droplet mild deformation. The bubble jetting at the end of collapse and the migration of the bubble centroid are particularly different in each bubble-droplet interaction. We propose theoretical models based on the method of images for calculating the Kelvin impulse and the anisotropy parameter which quantitatively reflects the migration of the bubble centroid at the end of the collapse. Finally, we explain that a combination of the Weber number and the anisotropy parameter determines the regimes of the bubble-droplet interactions.Comment: 26 pages, 14 figure

Hesperetin protects SH-SY5Y cells against 6- hydroxydopamine-induced neurotoxicity via activation of NRF2/ARE signaling pathways

Purpose: To investigation the protective effects of hesperetin against 6-hydroxydopamine (6-OHDA)- induced neurotoxicity. Methods: SH-SY5Y cells were incubated with 6-OHDA to create an in vitro model of neurotoxicity. This model was used to test the neuroprotective effects of hesperetin. Cell viability was assessed by MTT and lactate dehydrogenase (LDH) release assays. Flow cytometry and western blot were used to quantify apoptosis. Oxidative stress was evaluated by determining intracellular glutathione (GSH), malondialdehyde (MDA), superoxide dismutase (SOD), and reactive oxygen species (ROS). Results: In SH-SY5Y cells, treatment with 6-OHDA decreased cell viability and promoted LDH release. However, exogenous hesperetin protected against 6-OHDA-mediated toxicity. Similarly, although incubation with 6-OHDA induced apoptosis and increased cleaved caspase-3 and -9 levels, treatment with hesperetin protected against these effects. Treatment with 6-OHDA also led to significant oxidative stress, as indicated by reduced GSH and SOD levels and increased MDA and ROS levels in SH-SY5Y cells. However, these changes were reversed by pre-treatment with hesperetin. Of interest, hesperetin led to changes in 6-OHDA-induced expression of NRF2, heme oxygenase-1 (HO-1), glutamate-cysteine ligase (GCL) catalytic subunit (GCLC), and GCL modulatory (GCLM). Conclusion: Hesperetin protects against cell toxicity, apoptosis, and oxidative stress via activation of NRF2 pathway in a 6-OHDA-induced model of neurotoxicity. Future studies should investigate the use of hesperetin as a potential therapeutic approach for prevention or management of Parkinson’s disease. Keywords: Hesperetin, 6-OHDA, Neurotoxicity, NRF2, Parkinson’s diseas

Cdk5rap2 Interacts with Pericentrin to Maintain the Neural Progenitor Pool in the Developing Neocortex

Primary autosomal-recessive microcephaly (MCPH) and Majewski osteodysplastic primordial dwarfism type II (MOPDII) are both genetic diseases that result in decreased brain size at birth. MCPH is thought to arise from alterations in the size of the neural progenitor pool, but the cause of this defect has not been thoroughly explored. We find that one of the genes associated with MCPH, Cdk5rap2, is highly expressed in the neural progenitor pool and that its loss results in a depletion of apical progenitors and increased cell-cycle exit leading to premature neuronal differentiation. We link Cdk5rap2 function to the pericentriolar material protein pericentrin, loss of function of which is associated with MOPDII. Depletion of pericentrin in neural progenitors phenocopies effects of Cdk5rap2 knockdown and results in decreased recruitment of Cdk5rap2 to the centrosome. Our findings uncover a common mechanism, involving aberrations in the neurogenesis program, that may underlie the development of microcephaly in multiple diseases.National Institutes of Health (U.S.) (grant NS37007)Howard Hughes Medical Institute (Investigator

Strategies for Searching Video Content with Text Queries or Video Examples

The large number of user-generated videos uploaded on to the Internet everyday has led to many commercial video search engines, which mainly rely on text metadata for search. However, metadata is often lacking for user-generated videos, thus these videos are unsearchable by current search engines. Therefore, content-based video retrieval (CBVR) tackles this metadata-scarcity problem by directly analyzing the visual and audio streams of each video. CBVR encompasses multiple research topics, including low-level feature design, feature fusion, semantic detector training and video search/reranking. We present novel strategies in these topics to enhance CBVR in both accuracy and speed under different query inputs, including pure textual queries and query by video examples. Our proposed strategies have been incorporated into our submission for the TRECVID 2014 Multimedia Event Detection evaluation, where our system outperformed other submissions in both text queries and video example queries, thus demonstrating the effectiveness of our proposed approaches

Unveiling precipitation behavior in Mg-Y based alloys

Mg-Y based alloys exhibit a promising combination of strength and deformability through tuning precipitation and solute strengthening mechanisms and tailoring the activity of non-basal dislocations. Understanding the precipitation sequence of Mg-Y based alloys and its dependence on Yttrium concentration in the matrix will provide a guideline for fine tuning structure, morphology and distribution of precipitates in Mg-Y based alloys. In this paper, we explore the precipitation behaviors of Mg-11Y (wt%) and Mg-11Y-1Al (wt%) alloys using aberration-corrected scanning transmission electron microscopy, and rationalize the experimental observations based on first-principles density functional theory calculations. The precipitation sequence during ageing at 225 °C is identified to be SSSS → clusters/G.P. Zones →β′ (Mg7Y) → β′′/βt′′ (Mg3Y). A novel βt′′ phase forms through in-situ transformation from the β′ phase, which shares the same Mg3Y composition with D019-β′′ phase and exhibits the same cbco-structure as β′ phase in Mg-Y based alloys

CAMKs support development of acute myeloid leukemia.

BACKGROUND: We recently identified the human leukocyte immunoglobulin-like receptor B2 (LILRB2) and its mouse ortholog-paired Ig-like receptor (PirB) as receptors for several angiopoietin-like proteins (Angptls). We also demonstrated that PirB is important for the development of acute myeloid leukemia (AML), but exactly how an inhibitory receptor such as PirB can support cancer development is intriguing. RESULTS: Here, we showed that the activation of Ca (2+)/calmodulin-dependent protein kinases (CAMKs) is coupled with PirB signaling in AML cells. High expression of CAMKs is associated with a poor overall survival probability in patients with AML. Knockdown of CAMKI or CAMKIV decreased human acute leukemia development in vitro and in vivo. Mouse AML cells that are defective in PirB signaling had decreased activation of CAMKs, and the forced expression of CAMK partially rescued the PirB-defective phenotype in the MLL-AF9 AML mouse model. The inhibition of CAMK kinase activity or deletion of CAMKIV significantly slowed AML development and decreased the AML stem cell activity. We also found that CAMKIV acts through the phosphorylation of one of its well-known target (CREB) in AML cells. CONCLUSION: CAMKs are essential for the growth of human and mouse AML. The inhibition of CAMK signaling may become an effective strategy for treating leukemia

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat