Acoustic Tweezing Cytometry Induces Rapid Initiation of Human Embryonic Stem Cell Differentiation.

Mechanical forces play critical roles in influencing human embryonic stem cell (hESC) fate. However, it remains largely uncharacterized how local mechanical forces influence hESC behavior in vitro. Here, we used an ultrasound (US) technique, acoustic tweezing cytometry (ATC), to apply targeted cyclic subcellular forces to hESCs via integrin-bound microbubbles (MBs). We found that ATC-mediated cyclic forces applied for 30 min to hESCs near the edge of a colony induced immediate global responses throughout the colony, suggesting the importance of cell-cell connection in the mechanoresponsiveness of hESCs to ATC-applied forces. ATC application generated increased contractile force, enhanced calcium activity, as well as decreased expression of pluripotency transcription factors Oct4 and Nanog, leading to rapid initiation of hESC differentiation and characteristic epithelial-mesenchymal transition (EMT) events that depend on focal adhesion kinase (FAK) activation and cytoskeleton (CSK) tension. These results reveal a unique, rapid mechanoresponsiveness and community behavior of hESCs to integrin-targeted cyclic forces

Online Submodular Maximization Problem with Vector Packing Constraint

We consider the online vector packing problem in which we have a d dimensional knapsack and items u with weight vectors w_u in R_+^d arrive online in an arbitrary order. Upon the arrival of an item, the algorithm must decide immediately whether to discard or accept the item into the knapsack. When item u is accepted, w_u(i) units of capacity on dimension i will be taken up, for each i in [d]. To satisfy the knapsack constraint, an accepted item can be later disposed of with no cost, but discarded or disposed of items cannot be recovered. The objective is to maximize the utility of the accepted items S at the end of the algorithm, which is given by f(S) for some non-negative monotone submodular function f. For any small constant epsilon > 0, we consider the special case that the weight of an item on every dimension is at most a (1- epsilon) fraction of the total capacity, and give a polynomial-time deterministic O(k / epsilon^2)-competitive algorithm for the problem, where k is the (column) sparsity of the weight vectors. We also show several (almost) tight hardness results even when the algorithm is computationally unbounded. We first show that under the epsilon-slack assumption, no deterministic algorithm can obtain any o(k) competitive ratio, and no randomized algorithm can obtain any o(k / log k) competitive ratio. We then show that for the general case (when epsilon = 0), no randomized algorithm can obtain any o(k) competitive ratio. In contrast to the (1+delta) competitive ratio achieved in Kesselheim et al. [STOC 2014] for the problem with random arrival order of items and under large capacity assumption, we show that in the arbitrary arrival order case, even when |w_u|_infinity is arbitrarily small for all items u, it is impossible to achieve any o(log k / log log k) competitive ratio

Evaluation of 28 mango genotypes for physicochemical characters, antioxidant capacity, and mineral content

Mango germplasm remains underutilized due to the limited knowledge of quality properties. The objective of this study was to analyze and compare the physicochemical characters, antioxidant capacity, and mineral content of 28 mango genotypes, in order to assess useful information for the utilization of mango genetic resources in China. All the genotypes were grown under the same geographical conditions and with the same standard cultural practices. The results showed that there were significant differences among the genotypes in all studied traits. Potassium, calcium, manganese, and iron were the dominant mineral components; sucrose and/or fructose were the dominant sugars; and malic and citric acid were the dominant organic acids. Variation in sugars (glucose, 15.37–218.20 mg·g-1 fresh weight [FW]; fructose, 39.42–327.67 mg·g-1 FW; and sucrose 26.32–472.69 mg·g-1 FW), total phenolic compounds (13.69–82.65 mg gallic acid·100 g-1 FW), and total carotenoids (10.91–71.21 μg·g-1 FW) was significant among the genotypes. The total antioxidant potency composite index varied among the genotypes (6.12–81.39) and was significantly correlated with total phenolic compounds, but not with total carotenoids. Overall, the results demonstrated that the physicochemical characteristics, antioxidant capacity, and mineral content in mango are genotype-dependent

Phenolic Profile, Antioxidant Activity and Anti-proliferative Activity of Crabapple Fruits

To explore the potential of crabapples as functional food, polyphenols in crabapples and ‘Fuji’ apples were extracted, and the phenolic profile, total polyphenols, antioxidant activity and anti-proliferative activity against several human cancer cells were determined. The results indicated that crabapple extracts have more abundant phenols and higher total polyphenols (from 4.46 to 46.63 mg GAE·g−1 DW) compared to ‘Fuji’ apples. Crabapple extracts possessed higher antioxidant activity than apple by DPPH and ABTS analysis. All fruit extracts exhibited inhibitory effects on proliferation in different cancer cells; however, crabapple extracts performed significantly better, with half inhibitory concentration (IC50) values varied from 48.34 µg·mL−1 to 974.81 µg·mL−1 for colon cancer cells SW480, 64.67–1 466.35 µg·mL−1 for stomach cancer cells BGC-803, 78.88–910.64 µg·mL−1 for esophageal cancer cells CaEs-17. Besides, the red crabapples had higher antioxidant activity and anti-proliferative activity than yellow fruits. These results showed that crabapples, especially red crabapples, have great potential as a healthy food, as they are rich in phenolic compounds with high antioxidant and anti-proliferative activities to cancer cells