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In this paper, a time-dependent robust optimization model is proposed by introducing a concept of expected interval quality loss as the robustness metric. The purpose is to provide a potential analysis tool for power semiconductor devices involving stochastic processes. Unlike conventional robustness indicators, the metric is formulated by calculating the expectation and variation of the maximal instantaneous quality loss and capturing the auto-correlation of the quality loss over the time interval. In terms of model solving, the time-dependent robust optimization involves a nested optimization, namely the outer design optimization requires to call the inner robustness analysis frequently. It will lead to extremely low computational efficiency. For reducing robustness evaluations, a decoupling framework is proposed to convert the nested optimization into a sequential iterative process of design optimization and time-dependent robustness analysis. For further improving the efficiency of each robustness analysis, a semi-second-order approximation of quality characteristics is created based on the information at the previous iteration. Two engineering applications of power semiconductor devices verify the validity and feasibility of the proposed approach.

Cancer is a leading cause of death worldwide. Recent research studies have revealed that GM3 derivatives have considerable promise as potential therapeutic agents for cancer. To discover novel GM3 derivatives as potential antitumor agents, a one-pot enzymatic synthesis was established, yielding 14 GM3 derivatives in high total yields (22-41%). Subsequently, the inhibitory activities of GM3 derivatives were assessed by wound-healing assays and Transwell assays and tumor-bearing animal models. Among all the GM3 derivatives

Sortase A (SrtA) is a cysteine transpeptidase of most gram-positive bacteria that is responsible for the anchoring of many surface protein virulence factors to the cell wall. SrtA ablation has demonstrated to alleviate the infection without affecting the viability of bacteria. Herein, a series of benzofuran cyanide derivatives were synthesized and evaluated. Several compounds exhibited excellent inhibitory activity against SrtA with IC

Cancer therapy targets specific metabolic pathways or a single gene. This may result in low therapeutic effects due to drug selectivity and drug resistance. Recent studies revealed that the mitochondrial membrane potential and transmembrane permeability of cancerous mitochondria are differed from normal mitochondria. Thus, chemotherapy targeting cancerous mitochondria could be an innovative and competent strategy for cancer therapy. Previously, our work with a novel group of mitochondria targeting small molecules presented promising inhibitory capability toward various cancer cell lines and suppressed adenosine triphosphate (ATP) generation. Therefore, it is critical to understand the anticancer effect and targeting mechanism of these small molecules. This study investigated the inhibitory activity of mitochondria targeting small molecules with human cervical cancer cells – HeLa to further explore their therapeutic potential. HeLa cells were exposed to 10 µM of synthesized compounds and presented elevation in intracellular reactive oxygen species (ROS) level, impaired mitochondrial membrane potential and upregulation of apoptosis as well as necrosis. In vivo, HeLa cell tumor-bearing BALB/c nude mice were treated with mitochondria targeting small molecules for 12 days consecutively. Throughout this chemotherapy study, no deleterious side effects nor the appearance of toxicity was observed. Furthermore, mitochondria targeting small molecules treated groups exhibited significant down-regulation with both tumor volume and tumor weight compared to the Doxorubicin (DOX) treated group. Thus, inhibition of mitochondrial ATP synthesis, activation of intracellular ROS production, down-regulation of mitochondrial membrane potential and upregulation of apoptosis and necrosis rates are the indications of cancer therapy. In this work, we examined the anticancer capability of four mitochondria targeting small molecules in vitro and in vivo, and demonstrated a novel therapeutic approach in cancer therapy with tremendous potential.

Pathogens pose a severe threat to food safety and human health. The traditional methods for pathogen detection can't meet the growing diagnosis and control need. Digital PCR (dPCR) attracts a considerable attention for its ability to absolutely quantify pathogens with features of high selectivity, simplicity, accuracy and rapidity. The dPCR technique that achieves absolute quantification based on end-point measurement without standard curve offers a guideline for further genetic analysis and molecular diagnosis. It could contribute to the quantification of low level of nucleic acid, early detection and timely prevention of pathogenic diseases. In this review, 1442 publications about dPCR were selected and the detections of various pathogens by dPCR were reviewed comprehensively, including viruses, bacteria, parasites and fungi. A number of examples are cited to illustrate that dPCR is a new powerful tool with desired accuracy, sensitivity, and reproducibility for quantification of different types of pathogens. Moreover, the benefits, challenges and future prospects of the dPCR were also highlighted in this review.

Significance Phase separation of proteins is increasingly thought to play a fundamental role in biological processes. Recent studies show that tau protein phase separates, but the biological significance is unknown since artificial crowding agents are typically used and the resulting tau is not toxic. We now demonstrate that TIA1 potentiates RNA-mediated phase separation of tau, thereby enabling a process that occurs at physiological concentrations and also directs the formation of biologically active, highly neurotoxic oligomeric tau. Coordinated phase separation of functionally related proteins provides a general mechanism through which membraneless organelles can direct biological activities., Tau protein plays an important role in the biology of stress granules and in the stress response of neurons, but the nature of these biochemical interactions is not known. Here we show that the interaction of tau with RNA and the RNA binding protein TIA1 is sufficient to drive phase separation of tau at physiological concentrations, without the requirement for artificial crowding agents such as polyethylene glycol (PEG). We further show that phase separation of tau in the presence of RNA and TIA1 generates abundant tau oligomers. Prior studies indicate that recombinant tau readily forms oligomers and fibrils in vitro in the presence of polyanionic agents, including RNA, but the resulting tau aggregates are not particularly toxic. We discover that tau oligomers generated during copartitioning with TIA1 are significantly more toxic than tau aggregates generated by incubation with RNA alone or phase-separated tau complexes generated by incubation with artificial crowding agents. This pathway identifies a potentially important source for generation of toxic tau oligomers in tau-related neurodegenerative diseases. Our results also reveal a general principle that phase-separated RBP droplets provide a vehicle for coassortment of selected proteins. Tau selectively copartitions with TIA1 under physiological conditions, emphasizing the importance of TIA1 for tau biology. Other RBPs, such as G3BP1, are able to copartition with tau, but this happens only in the presence of crowding agents. This type of selective mixing might provide a basis through which membraneless organelles bring together functionally relevant proteins to promote particular biological activities.

SummaryThe microtubule associated protein tau oligomerizes in response to stress and disease, but the function of oligomeric tau (oTau) and the ultimate mechanisms of toxicity are unknown. To gain insights, we have now used Cry2-based optogenetics to induce tau oligomers (oTau-c) in neuronal cultures. oTau-c can seed tau aggregation and biochemical fractionates in a manner similar to oTau. Optical induction of oTau elicits a translational stress response that includes cytoplasmic translocation of the TIA1, abundant stress granules (SGs) and reduced protein synthesis. Proteomic analysis identifies HNRNPA2B1 as a principle target of oTau. Imaging and immunoprecipitation verify the HNRNPA2B1 association with endogenous oTau in neurons, animal models and human Alzheimer brain tissue. Mechanistic studies demonstrate that HNRNPA2B1 functions as a linker, connecting oTau with N6-methyladenosine modified transcripts (m6A). Knockdown of HNRNPA2B1 prevents oTau from associating with m6A, prevents oTau-induced reductions in protein synthesis and reduces oTau-induced toxicity. Finally, we show striking increases in m6A-oTau and -HNRNPA2B1 complexes in brains of Alzheimer subjects and P301S tau mice. These results reveal a novel complex containing oTau, HNRNPA2B1 and m6A that contributes to the integrated stress response of oTau.HighlightsDevelopment of a powerful method combining optical induction of tau oligomerization with precision mass spectrometry to obtain time resolved evolution of protein interaction networks.Demonstration of a tripartite complex that links tau oligomers with HNRNPA2B1 and N6-methyladenosine modified RNA in cytoplasmic stress granules.Knockdown of HNRNPA2B 1 abrogates the interactions of oTau with N6-methyladenosine modified RNA, as well as inhibits oTau-mediated neurodegeneration.Discovery that N6-methyladenosine modified RNA is significantly increased in the brains of P301S tau transgenic mice and in patients with Alzheimer’s disease.

The microtubule associated protein tau oligomerizes in response to stress and disease, but the function of oligomeric tau (oTau) and the ultimate mechanisms of toxicity are unknown. To gain insights, we have now used Cry2-based optogenetics to induce tau oligomers (oTau-c) in neuronal cultures. oTau-c can seed tau aggregation and biochemical fractionatesin a manner similar to oTau. Optical induction of oTau elicits a translational stress response that includes cytoplasmic translocation of the TIA1, abundant stress granules(SGs) and reduced protein synthesis. Proteomic analysis identifies HNRNPA2B1 as a principle target of oTau. Imaging and immunoprecipitation verify the HNRNPA2B1 association with endogenous oTau in neurons, animal models and human Alzheimer brain tissue. Mechanistic studies demonstrate that HNRNPA2B1 functions as a linker, connecting oTau with N6-methyladenosine modified transcripts (m6A). Knockdown of HNRNPA2B1 prevents oTau from associating with m6A, prevents oTau-induced reductions in protein synthesis and reduces oTau-induced toxicity. Finally, we show striking increases in m6A-oTau and -HNRNPA2B1 complexes in brains of Alzheimer subjects and P301S tau mice. These results reveal a novel complex containing oTau, HNRNPA2B1 and m6A that contributes to the integrated stress response of oTau.

We combine optogenetics with proteomics for time-resolved identification of tau oligomer (oTau) protein interactomes. Optically induced tau oligomerization is elicits a translational stress response exhibiting increased cytoplasmic localization of N6-methyladenosine (m6A) modified transcripts that partially co-localize with oTau, stress granules composed of HNRNPA2B1 and TIA1 but not G3BP1. Appearance of the cytoplasmic m6A complex occurs with a concomitant reduction in protein synthesis. Persistent tau oligomerization elicits neurodegeneration. We show that cytoplasmic translocation of m6A labeled transcripts is a prominent neuropathological feature of tauopathy in P301S tau mice and Alzheimer’s disease brain. Characterization of the oTau proteome identifies the RNA binding protein, HNRNPA2B1 as a principle target of oTau. Knockdown of HNRNPA2B1 abrogates the association of oTau with m6A-labeled transcripts, preventing the oTau-induced reduction in protein synthesis and reducing neurodegeneration. These results suggest that oTau elicits stress and toxicity through binding to HNRNPA2B1, which functions as a reader of m6A-labeled transcripts.

Vibrio parahaemolyticus, a worldwide pathogen, has been proved to be capable of entering into viable but nonculturable (VBNC) state and survive under stressful conditions. In this study, a method of real-time quantitative PCR coupled with propidium monoazide (PMA-qPCR) was developed and evaluated for the reliable quantification of the VBNC cells of V. parahaemolyticus. The samples of different ratios of viable and dead cells were detected by PMA-qPCR and qPCR to assess this method. Then the method was used to monitor the VBNC induction process of V. parahaemolyticus and quantify the viable cells along with confirmation of cell integrity and respiratory activity by fluorescence microscopy and confocal laser scanning microscope (CLSM) observation, flow cytometry (FCM) analysis. In addition, the applicability of the method was verified to detect artificially contaminated seafood samples with different states of V. parahaemolyticus. The results showed that the optimal PMA treatment condition was 5 min-PMA incubation in dark followed by 15 min-light exposure. This method can significantly distinguish viable from dead cells and specifically enumerate viable cells. By PMA-qPCR method, the number change of cells during VBNC induction was monitored successfully. The cells incubated at 4 °C in sterile 3% NaCl entered into VBNC state, and 106 cell/mL of VBNC cells (10% of the original viable cells) were detected on the fifth day of induction, then the density of VBNC cells was 5.8 × 104 cell/mL on the 40th day when no culturable cells were observed. FCM analysis showed the viability of the VBNC cells which were also observed red revealing respiratory activity by CTC/DAPI staining under CLSM. For the detection of the spiked seafood samples (shrimp, pomfret and scallop) with different states of V. parahaemolyticus, it could detect as low as 1.2 × 102 cell/g of the viable or VBNC state of V. parahaemolyticus without any interference from food matrices and dead cells. In summary, the PMA-qPCR method developed in this study is rapid and reliable to quantify VBNC cells of V. parahaemolyticus.

A series of benzofuran piperidine derivatives were designed, synthesized and evaluated as multifunctional Aβ antiaggregant to treat Alzheimer's disease (AD). In vitro results revealed that all of them are very good Aβ antiaggregants and some of the compounds are potent acetylcholinesterase (AChE) inhibitors with moderate antioxidant property. Selected compounds were also tested for neuroprotection activity, LDH release, ATP production and inhibitory activity to prevent Aβ peptides binding to the cell membrane. The different modifications introduced in the structure of our lead compound 3 (hAChE IC50 = 61 μM and self induced Aβ 25-35 aggregation 45.45%), to increase its activity toward AD related targets. The most interesting multifunctional Aβ antiaggregants were compounds 3a, 3h and 3i, highlighting 3h as potent Aβ antiaggregant and good antiacetylholinesterase inhibitor (self induced Aβ 25-35 aggregation 57.71% and hAChE IC50 = 21 μM), with good neuroprotective and antioxidant activity. In addition, these three most promising compounds prevent intracellular reactive oxygen species (ROS) formation and cell apoptosis induced by Aβ25-35 peptides in SH-SY5Y cells. Molecular docking studies were also accomplished to understand the binding interaction of these compounds on Aβ monomer, Aβ fibril and AChE. Based on all data, compounds 3a, 3h and 3i were concluded as potent multifunctional Aβ antiaggregant, useful candidate for the treatment of AD.

Mitochondria are pivotal energy production sources for cells to maintain necessary metabolism activities. Targeting dysfunctional mitochondrial features has been a hotspot for mitochondrial-related disease researches. Investigation with cancerous mitochondrial metabolism is a continuing concern within tumor therapy. Herein, we set out to assess the anti-cancer activities of a novel family of TPP-thiazole derivatives based on our earlier research on mitochondrial targeting agents. Specifically, we designed and synthesized a series of TPP-thiazole derivatives and revealed by the MTT assay that most synthesized compounds effectively inhibited three cancer cell lines (HeLa, PC3 and MCF-7). After structure modifications, we explored the SAR relationships and identified the most promising compound R13 (IC50 of 5.52 μM) for further investigation. In the meantime, we performed ATP production assay to assess the selected compounds inhibitory effect on HeLa cells energy production. The results displayed the test compounds significantly restrained ATP production of cancer cells. Overall, we have designed and synthesized a series of compounds which exhibited significant cytotoxicity against cancer cells and effectively inhibited mitochondrial energy production.

Our previous discovery of pyrazolo [1,5-a]pyrimidin-7(4H)-one scaffold-based DPP-4 inhibitors yielded two potent compounds b2 (IC50 = 79 nM) and d1 (IC50 = 49 nM) but characterized by cytotoxicity. Herein, with scaffold hopping and fragment-based drug design strategies, highly potent and selective pyrazolo [1,5-a]pyrimidine DPP-4 inhibitors were found featured by reduced or diminished cytotoxicity. Specifically, c24 (IC50 = 2 nM) exhibits a 25 to 40-fold increase of inhibitory activity respect to those of b2 and d1, respectively, 2-fold from Alogliptin (IC50 = 4 nM), and remarkable selectivity over DPP-8 and DPP-9 (>2000 fold). Further docking studies confirmed that the pyrazolo [1,5-a]pyrimidine core interacts with the S1 pocket whereas its substituted aromatic ring interacts with the sub-S1 pocket. The interactive mode in this case resembles that of Alogliptin and Trelagliptin. Further in vivo IPGTT assays in diabetic mice demonstrated that c24 effectively reduces glucose excursion by 48% at the dose of 10 mg/kg, suggesting that c24 is worthy of further development as a potent anti-diabetes agent.

Herein a series of Geniposide derivatives were designed, synthesized and evaluated as protein tyrosine phosphatase 1B (PTP l B) inhibitors. Most of these compounds exhibited potent in vitro PTP1B inhibitory activities, the representative 7a and 17f were found to be the most potent inhibitors against the enzyme with IC50 value of 0.35 and 0.41 μM, respectively. More importantly, they showcased 4 to10-fold selectivity over SHP2 and 3-fold over TCPTP. Further biological activity studies revealed that compounds 7a, 17b and 17f could effectively enhance insulin-stimulated glucose uptake with no significant cytotoxicity. Subsequent molecular docking and structural activity relationship analyses demonstrated that the glucose scaffold, benzylated glycosyl groups, and arylethenesulfonic acid ester significantly impact on the activity and selectivity.

Vibrio parahaemolyticus, a marine food-borne pathogen, has been proved to be a significant cause of human gastrointestinal disorders worldwide. In this study, a method of multiplex droplet digital PCR (ddPCR) based on primer and probe sequences of the tlh, tdh and ureR genes were developed and evaluated for the reliable quantification of V. parahaemolyticus cells in seafoods. The specificities of all primers and probes used in this study were validated on three standard strains of V. parahaemolyticus, 10 strains of Vibrio spp., and 22 strains of other bacteria by ddPCR and quantitative PCR (qPCR). Then the ddPCR system, primers, probe concentration and amplification procedures were optimized, and the templates with cell and genomic DNA (gDNA) were compared. The results showed that using cell as template could benefit for multiplex ddPCR, which performed higher linkage among three genes. This method improved sensitivity, specificity, accuracy, convenience, and reproducibility for the detection of V. parahaemolyticus, and the limit of detection (LOD) was 15 CFU/mL. In addition, the applicability of this method was compared with plate count and qPCR, and then verified to detect artificially contaminated seafood samples containing different concentrations of V. parahaemolyticus. The results indicated that the established method is stable, accurate, sensitive, range-wide, and has the potential to detect the three different genes of V. parahaemolyticus in food samples.

Incretin pathway plays an important role in the development of diabetes medications. Interventions in DPP-4 and GLP-1 receptor have shown remarkable efficacy in experimental and clinical studies and imperatively become one of the most promising therapeutic approaches in the T2DM drug discovery pipeline. Herein, we analyzed the actionmechanismsof DPP-4 and GLP-1 receptor targeting the incretin pathway in T2DM treatment. We gave an insight into the structural requirements for the potent DPP-4 inhibitors and revealed a classification of DPP-4 inhibitors by stressing on the binding modes of these ligands to the enzyme. We then reviewed the drug discovery strategies for the development of peptide and non-peptide GLP-1 receptor agonists (GLP-1 RAs). Furthermore, the drug design strategies for DPP-4 inhibitors and GLP-1R agonists were detailed accurately. This review might provide an efficient evidence for the highly potent and selective DPP-4 inhibitors and the GLP-1 RAs, as novel medicines for patients suffering from T2DM.

The objective of this study was to investigate the influence of moisture content on the interfacial properties of natural palm. An oval fiber pull-out model was first introduced. Then, the fiber cross-sectional shape and tensile properties were investigated. Single fiber pull-out test was used to study the effect of moisture content on the interfacial properties of natural palm fiber–matrix composite. Scanning electron microscopy was used to examine the fiber interfacial morphology. The result showed that the interface shear strength, chemical bond and frictional stress increase, while the slip-hardening coefficient keeps constant with the decrease in moisture content.

There exist several honeycomb networks exhibiting zero Poisson's ratio (ZPR). Applications of these networks can be found in different fields. The ZPR properties of these structures have been mechanically modeled and tested. However, the underlying mechanism driving the ZPR behavior has not been paid much attention. The present work focuses on the deformation mechanism of the ZPR networks. Through the discussion and comparison of the deformation process of the ZPR, auxetic and common honeycomb networks, the strain-isolation mechanism is proposed to explain the ZPR behavior. Then, according to this mechanism, the reversed semi-re-entrant (RSRE) honeycomb is created. With experimental measurements and finite-element analysis (FEA), the ZPR properties of the RSRE can be proven. The strain-isolation mechanism can not only explain the ZPR behavior but also be used in the design of new ZPR honeycomb networks. 3D ZPR structures are also derived from the 2D honeycomb networks. Their Poisson's ratios in 3D space are also discussed based on FEA results. The model of the 3D RSRE structure showing ZPR behaviors in three orthogonal planes.