1,076 research outputs found

    The Effect of Additives on Mixed Silage Quality of Sugar Beet and Corn Stalks

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    Sugar beet is a main economic crop in the northeast region of China. Ensilaging sugar beet mixed with other forages, provides green feedstuff for livestock in spring and winter. The ensilaging could avoid mildew and rot of fresh forages and would decrease environmental pollution (Liu 1996). The aim of this study was to evaluate the influence of silage additives on mixed silage quality of corn stalks and sugar beet

    DOF transcription factors: Specific regulators of plant biological processes

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    Plant biological processes, such as growth and metabolism, hormone signal transduction, and stress responses, are affected by gene transcriptional regulation. As gene expression regulators, transcription factors activate or inhibit target gene transcription by directly binding to downstream promoter elements. DOF (DNA binding with One Finger) is a classic transcription factor family exclusive to plants that is characterized by its single zinc finger structure. With breakthroughs in taxonomic studies of different species in recent years, many DOF members have been reported to play vital roles throughout the plant life cycle. They are not only involved in regulating hormone signals and various biotic or abiotic stress responses but are also reported to regulate many plant biological processes, such as dormancy, tissue differentiation, carbon and nitrogen assimilation, and carbohydrate metabolism. Nevertheless, some outstanding issues remain. This article mainly reviews the origin and evolution, protein structure, and functions of DOF members reported in studies published in many fields to clarify the direction for future research on DOF transcription factors

    Optimal Policies on Managing Drug Supply and Patient Access to Drugs

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    Health care decision-makers face several uncertainties regarding pharmaceutical products. For new and expensive drugs, the performance outside of clinical trials could be uncertain. For old and low-profit pharmaceutical products, the supply could be uncertain, causing drug shortages. In three essays, I study mitigating strategies to deal with different types of uncertainties associated with pharmaceutical products. In the first essay, I compare two types of pharmaceutical reimbursement contracts to mitigate the uncertainties associated with new and expensive drugs. I construct a game-theoretic model to analyze the interactions between a pharmaceutical manufacturer and a payer. The payer’s reimbursement of a drug is either related to the cost-effectiveness or the sales volume of the drug in the two contracts, respectively. I find key factors that determine the two parties’ preferences for the two contracts. I also find conditions under which each type is preferred by both parties and can achieve a Pareto improvement. In the second essay, I study mitigating strategies for drug shortage, which has become a serious problem in many countries in recent years. I construct a multi-period supply chain model to analyze the interactions between a representative hospital and an unreliable pharmaceutical manufacturer. The hospital owns an in-house manufacturer and can procure the drug from the two manufacturing facilities. I also assume that the hospital can make emergency production. I study the two parties’ procurement and production decisions and examine the impacts of the hospital’s optimal decisions on the external manufacturer’s profit. In the third essay, I study mitigating strategies for drug shortages from the governments’ perspective. I construct a game-theoretic model consisting of a pharmaceutical manufacturer, a wholesaler, and a government. I compare two types of mitigating strategies that the government can implement: providing subsidies to the wholesaler, or using a government-owned manufacturer. I identify key factors for the government’s preference over the two strategies and examine the impact on the private sector. The three essays have theoretical contributions to game theory and supply chain risk management literature and have policy implications for policymakers to manage drug supply and patient access to drugs

    ARM processor modeling at a cycle accurate level in systemC

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    Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal

    Influence of non-covalent preorganization on supramolecular effective molarities.

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    A family of closely related zinc porphyrin-pyridine complexes were used to examine the influence of linker preorganization on supramolecular effective molarities for formation of intramolecular H-bonds. Each pyridine ligand was equipped with a side-chain containing two H-bond acceptors, one on the end of the chain (terminal) and one in the middle of the chain (linker). These H-bond acceptors make intramolecular interactions with phenol H-bond donors on the porphyrin periphery. Two different H-bonding acceptors were used as linker groups in order to construct frameworks with significantly different degrees of preorganization: ester linkers populate the H-bonded state 60-70% of the time, whereas amide linkers populate the H-bonded state 90-100% of the time. Thus the amide linkers provide a significantly more preorganised ligand framework than the ester linkers. Effective molarities (EM) for intramolecular H-bonds between the terminal H-bond acceptor groups on the ligands (esters and amides) and the porphyrin phenol groups were quantified using 32 chemical double mutant cycles. The values of EM for interactions with the terminal H-bond acceptors are independent of the nature of the linker H-bond acceptor (weakly bonded ester or strongly bonded amide), which indicates that preorganization of the linker has no effect on chelate cooperativity in these systems.We thank the EPSRC, the China Scholarship Council, and the University of Sheffield for funding.This is the final version of the article. It first appeared from the Royal Society of Chemistry via http://dx.doi.org/10.1039/C5OB00231

    Twist angle effects on the dynamic response of in-plane-switching liquid crystal displays

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    Twist angle effect on the response time of in-plane-switching liquid crystal displays are analyzed. We propose a device configuration whose top and bottom boundary liquid crystal layers are symmetric to each other with respect to the electric field direction. The analytical results of this device configuration indicate that the response time is improved at least 4X faster than that of a conventional in-plane-switching twisted-nematic mode and normal in-plane-switching mode.Comment: 12 Pages, 3 Figures. will be appeared in Appl. Phys. Let

    Estimating Hydroxyl Radical Photochemical Formation Rates in Natural Waters During Long-Term Laboratory Irradiation Experiments

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    In this study it was observed that, during long-term irradiations (\u3e1 day) of natural waters, the methods for measuring hydroxyl radical (˙OH) formation rates based upon sequentially determined cumulative concentrations of photoproducts from probes significantly underestimate actual ˙OH formation rates. Performing a correction using the photodegradation rates of the probe products improves the ˙OH estimation for short term irradiations (\u3c1 day), but not long term irradiations. Only the ‘instantaneous’ formation rates, which were obtained by adding probes to aliquots at each time point and irradiating these sub-samples for a short time (≤2 h), were found appropriate for accurately estimating ˙OH photochemical formation rates during long-term laboratory irradiation experiments. Our results also showed that in iron- and dissolved organic matter (DOM)-rich water samples, ˙OH appears to be mainly produced from the Fenton reaction initially, but subsequently from other sources possibly from DOM photoreactions. Pathways of ˙OH formation in long-term irradiations in relation to H2O2 and iron concentrations are discussed

    GOFFA: Gene Ontology For Functional Analysis – A FDA Gene Ontology Tool for Analysis of Genomic and Proteomic Data

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    BACKGROUND: Gene Ontology (GO) characterizes and categorizes the functions of genes and their products according to biological processes, molecular functions and cellular components, facilitating interpretation of data from high-throughput genomics and proteomics technologies. The most effective use of GO information is achieved when its rich and hierarchical complexity is retained and the information is distilled to the biological functions that are most germane to the phenomenon being investigated. RESULTS: Here we present a FDA GO tool named Gene Ontology for Functional Analysis (GOFFA). GOFFA first ranks GO terms in the order of prevalence for a list of selected genes or proteins, and then it allows the user to interactively select GO terms according to their significance and specific biological complexity within the hierarchical structure. GOFFA provides five interactive functions (Tree view, Terms View, Genes View, GO Path and GO TreePrune) to analyze the GO data. Among the five functions, GO Path and GO TreePrune are unique. The GO Path simultaneously displays the ranks that order GOFFA Tree Paths based on statistical analysis. The GO TreePrune provides a visual display of a reduced GO term set based on a user's statistical cut-offs. Therefore, the GOFFA visual display can provide an intuitive depiction of the most likely relevant biological functions. CONCLUSION: With GOFFA, the user can dynamically interact with the GO data to interpret gene expression results in the context of biological plausibility, which can lead to new discoveries or identify new hypotheses. AVAILABILITY: GOFFA is available through ArrayTrack software

    Influence of receptor flexibility on intramolecular H-bonding interactions.

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    Atropisomers of a series of zinc tetraphenyl porphyrins were synthesized and used as supramolecular receptors. Rotation around the porphyrin-meso phenyl bonds is restricted by installing ortho-chlorine substituents on the phenyl groups. The chlorine substituents allowed chromatographic separation of atropisomers, which did not interconvert at room temperature. The porphyrin meso phenyl groups were also equipped with phenol groups, which led to the formation of intramolecular H-bonds when the zinc porphyrins were bound to pyridine ligands equipped with ester or amide side arms. Binding of the pyridine ligands with the conformationally locked chloroporphyrins was compared with the corresponding unsubstituted porphyrins, which are more flexible. The association constants of 150 zinc porphyrin-pyridine complexes were measured in two different solvents, toluene and 1,1,2,2-tetrachloroethane (TCE). These association constants were then used to construct 120 chemical double mutant cycles to quantify the influence of chlorine substitution on the free energy of intramolecular H-bonds formed between the phenol side arms of the porphyrins and the ester or amide side arms of the pyridine ligands. Conformational restriction leads to increases in the stability of some complexes and decreases in the stability of others with variations in the free energy contribution due to intramolecular H-bonding of -5 to +6 kJ mol(-1).We thank the EPSRC, the China Scholarship Council, and the University of Sheffield for funding.This is the final version of the article. It first appeared from RSC via http://dx.doi.org/10.1039/C5OB00805

    Porous silicon nanoparticles for cancer photothermotherapy

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    The in vitro cell tests and in vivo animal tests were performed to investigate the feasibility of the photothermal therapy based on porous silicon (PSi) in combination with near-infrared (NIR) laser. According to the Annexin V- fluorescein isothiocyanate Apoptosis assay test results, the untreated cells and the cells exposed to NIR laser without PSi treatment had a cell viability of 95.6 and 91.3%, respectively. Likewise, the cells treated with PSi but not with NIR irradiation also had a cell viability of 74.4%. Combination of these two techniques, however, showed a cell viability of 6.7%. Also, the cell deaths were mostly due to necrosis but partly due to late apoptosis. The in vivo animal test results showed that the Murine colon carcinoma (CT-26) tumors were completely resorbed without nearly giving damage to surrounding healthy tissue within 5 days of PSi and NIR laser treatment. Tumors have not recurred at all in the PSi/NIR treatment groups thereafter. Both the in vitro cell test and in vivo animal test results suggest that thermotherapy based on PSi in combination with NIR laser irradiation is an efficient technique to selectively destroy cancer cells without damaging the surrounding healthy cells
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