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Time-based switching control of genetic regulatory networks: Toward sequential drug intake for cancer therapy
No full textAs cancer growth and development typically involves multiple genes and pathways, combination therapy has been touted as the standard of care in the treatment of cancer. However, drug toxicity becomes a major concern whenever a patient takes 2 or more drugs simultaneously at the maximum tolerable dosage. A potential solution would be administering the drugs in a sequential or alternating manner rather than concurrently. This study therefore examines the feasibility of such an approach from a switched system control perspective. Particularly, we study how genetic regulatory systems respond to sequential (switched) drug inputs using the time-based switching mechanism. The design of the time-driven drug switching function guarantees the stability of the genetic regulatory system and the repression of the diseased genes. Simulation results using proof-ofconcept models and the proliferation and survival pathways with sequential drug inputs show the effectiveness of the proposed approach
A growing stem inhibits bud outgrowth – The overlooked theory of apical dominance
No full textThree theories of apical dominance, direct, diversion, and indirect, were proposed in the 1930s to explain how auxin synthesized in the shoot apex might inhibit axillary bud outgrowth, and thus shoot branching. The direct and diversion theories of apical dominance have been investigated in detail, and they are replaced with the current auxin transport canalization and second messenger theories, respectively. These two current theories still cannot entirely explain the phenomenon of apical dominance. Although there is ample evidence that the inhibition of bud outgrowth by auxin from the shoot apex is linked to stem elongation and highly branched auxin biosynthesis or signaling mutants are dwarf, the third theory proposed in the 1930s, the indirect theory, that explains apical dominance as auxin-induced stem growth indirectly inhibits bud outgrowth has been overlooked. The indirect theory did not propose how a growing stem might inhibit bud outgrowth. Recent discoveries indicate bud dormancy (syn. quiescence, paradormancy) in response to intrinsic and environmental factors in diverse species is linked to enhanced growth of the main shoot and reduced sugar level in the buds. Since a growing stem is a strong sink for sugars, and sugar is indispensable for shoot branching, the indirect theory of apical dominance might now be explained as auxin-induced stem growth inhibits bud outgrowth by diverting sugars away from buds. Detailed study of the indirect theory and the effect of source–sink status on dormancy and outgrowth of axillary buds will advance our knowledge of apical dominance and shoot branching in plants
Characterization of PCL/zeolite electrospun membrane for the removal of silver in drinking water
No full textThe presence of heavy metals in drinking water leads to several health problems. In this study, polycaprolactone (PCL)/zeolite nano or microfiber electrospun composite membranes, diameter range of the fibers was 2 µm- 6 µm, were fabricated by using electrospinning technique. The membranes separation processes have played very crucial roles in water purification industry. Apart from that, the membranes are prepared with biocompatible, non-toxic materials which will be eco-friendly. In order to produce electrospun membrane, 15% (w/v) of PCL polymer solution was dissolved in acetone and 20% (w/w) zeolite was incorporated into the PCL polymer solution. Electricity charged jet of polymer solution from the syringe formed an electrostatics field when the high voltage of 20kV was applied. Scanning electron micrograph (SEM) and energy dispersive spectroscopy (EDX) implemented to indicate the characterization of membranes. The water contact angle of PCL/zeolite membrane was 119.53±5.24 which was almost same as pure PCL membrane (107.73±8.54). The inducible results obtained in this study suggested that electrospun pcl and polycaprolactone/zeolite layer by layer nanofibrous membranes can be a favored verdict for the removal of heavy metal ions
Leptin and IGF-I improve bovine embryo quality in vitro
No full textThe in vitro embryo culture systems need further improvement to enhance the efficiency of bovine embryo production. Growth factors play key roles in embryo production and quality. The objective of this study was to define the effects of leptin, insulin-like growth factor-1 (IGF-1), and their combination on embryonic development, apoptosis, and expression profiles of a panel of developmentally important genes during 8-day embryo culture. The oocytes were aspirated from slaughterhouse ovaries of mixed breed cows. Following IVM/IVF presumptive zygotes were obtained. To accomplish this objective, presumptive zygotes (16-18 h post-insemination) were cultured in vitro as control (no supplementation, n = 349), 5 ng/ml leptin (Group I, n = 322), 100 ng/ml IGF-1 (Group II, n = 347), and 5 ng/ml leptin and 100 ng/ml IGF-1 (Group III, n = 360). All groups were supplemented with 10% fetal calf serum (FCS) on Day 4, and blastocysts were harvested on day 8. The DNA-fragmented nuclei of blastocyst were determined by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay and expression profiles of a panel of developmentally important genes were assayed by real-time polymerase chain reaction (RT-PCR). The cleavage rate and embryo development to 8-16 cell stage were higher in groups II and III as compared to control (P \u3c 0.05), respectively. Percentage of blastocyst and mean cell numbers per blastocyst did not differ among the groups. Addition of IGF-I and/or combination with leptin decreased the number of nuclei with fragmented DNA (P \u3c 0.01) as compared to the control group. Although the expression of glucose transporter 1 (Glut1), desmosomal glycoprotein desmocollin III (DcIII), and insulin like growth factor 2 receptor (Igf2r) transcripts did not change among the groups, interferon-tau (IF-tau) and DNA methyltransferase 3A (Dnmt3a) were down-regulated in group II while heat shock protein-70 (Hsp70) and IF-tau were up regulated in group III. Results indicate that addition of IGF-I in culture media improved the cleavage rate; combination with leptin also improved the development rates to 8-16-cell-stage embryos, decreased the TUNEL-positive nuclei, and caused alterations in the amounts of transcripts for the developmentally important genes assayed
An Analysis of the 2015 Nigerian Presidential Election
Get PDFMuch time has gone into analyzing the 2015 Nigerian Presidential election, a veritable repeat of the 2011 election between incumbent Goodluck Jonathan and retired General Muhammadu Buhari. Previous elections in Nigeria have been fraught with violence and charges of electoral fraud. While the Nigerian electoral commission worked hard to ensure that these elections were fair, violence and charges of fraud materialized. Electoral forensics applies statistical techniques to elections, frequently testing for evidence of fraud or of unfairness. Using binomial regression, we tested the official results from the 2015 Nigerian Presidential election for evidence of differential invalidation. Differential invalidation involves invalidating ballots based on whom they are cast. The results do not strictly indicate evidence of this type of electoral unfairness. The marginal p-values (0.1420 and 0.0346) only suggest that there may be a problem. Furthermore, the invalidation process in Ebonyi state appears to be completely different from that in other states. This leads one to wonder why that difference exists
The Panther Newspaper - October 2017
Get PDFhttps://digitalcommons.pvamu.edu/pv-panther-newspapers2017/1000/thumbnail.jp
Panther - December 2017
Get PDFhttps://digitalcommons.pvamu.edu/pv-panther-newspapers2017/1001/thumbnail.jp
