Studies of Association of Environmental Risk Factors in Down Syndrome

Down syndrome (DS) is the most common live-born birth defect in humans. The genetic cause of DS is trisomy of chromosome 21. 94% of cases of DS trisomy are due to maternal chromosomal non-disjunction. Advanced maternal age has been identified as a key risk factor for DS. However, it is not clearly understood yet how maternal age effect increases chromosome non-disjunction. Recently, it has been suggested that factors involved in meiotic chromosome segregation may be altered in aged oocytes and such molecular abnormality could be caused or accelerated by maternal environmental factors. Epidemiologic studies have tried to investigate effect of maternal environmental factors on DS. The most commonly-studied factors are maternal peri-conceptional smoking and oral contraceptive use. However, the evidence of association of those factors with DS has not been consistent. In this thesis, a DS cohort in Kolkata, India was investigated for studying association of maternal peri-conceptional behavioral factors on DS. The characteristics of exposure to two factors, smokeless chewing tobacco use (SCT) and oral contraceptive use (OC), are unique in this cohort as compared to previous study populations. In this population both exposures tend to be started early in life and in high dose. By using logistic and linear regression methods, I found significant association of maternal SCT and OC use with DS. SCT interacts with maternal age, having a stronger effect in younger mothers compared to older mothers, while the effect of OC use on risk is the same at all ages. SCT use is also associated with meiotic type (I vs. II) of chromosome non-disjunction and with lack of recombination in meiosis I type non-disjunction. Furthermore, maternal SCT use is strongly associated with maternal telomere length, which has been shown to be a molecular marker of aging. SCT use decreases maternal telomere length, especially among women bearing DS child with meiosis I type non-disjunction. In conclusion, with Indian DS cohort, this thesis was able to find evidence of interactions among three major risk factors in DS: tobacco use, oral contraceptive use, and maternal age. This study has great public health significance because better understanding of the risk factors for DS can lead to improved prevention and screening strategies

Effect of electrolytes on the electrochemical performance of nickel cobaltite–titania nanotubes composites as supercapacitive materials

The effects of electrolytes on the electrochemical performance of nickel cobaltite–titania nanotubes composites as electrochemical capacitors were evaluated. Four types of electrolytes were selected to assess their effects on the prepared composites, namely aqueous electrolytes of 1.0 M KCl, 1.0 M HCl, 1.0 M KOH; and an organic electrolyte, 0.27 M tetra-n-butylammonium tetrafluoroborate (TBATFB) ionic liquid salt in acetonitrile. The composites performed better in 1.0 M HCl and 1.0 M KOH, than in 1.0 M KCl and 0.27 M TBATFB, which suggested that aqueous electrolytes with non-neutral pH would improve the specific areal capacitance values of the composites. Results have shown optimal performance in 1.0 KOH, which endowed the composite with excellent rate capability up to 200 mV s−1. Cyclic voltammogram of the composite analysed in 1.0 M KOH produced a leaf-shaped like profile, with higher current densities towards more positive potentials. Charge–discharge analyses in 1.0 M KOH has shown that the composite possessed specific areal capacitance of up to 214.76 µF cm−2 when it was evaluated at the current density of 350 µA cm−2. The composite also retained up to 97.79% of its specific areal capacitance when current density was increased to 400 µA cm−2. This material has demonstrated potential application for electrochemical capacitors through its facile fabrication technique

Capacitive enhancement of reduced titania nanotubes by reversed pulse electrodeposited Mn2O3 and Co3O4

Many attempts have been done to improve the capacitive performance of reduced titania nanotubes (R-TNTs) by incorporation of metal oxides via electrodeposition method. In this study, pulse reverse electrodeposition technique has been applied to deposit Mn2O3 and Co3O4 onto the R-TNTs as this technique has the ability to control the composition of targeted materials while at the same time helps in facilitating the uniformity of deposition and the size of the metal oxides onto the reduced nanotubes. Based on FESEM and TEM analyses, it is proven that both metal oxides were uniformly deposited without covering the nanotubes opening. Besides, Mn2O3 and Co3O4 with crystallite size of 13.6 nm and 12.4 nm were recorded in XRD analysis. Electrochemical analyses were performed to evaluate the capacitive performance of both deposited metal oxides. The CV profiles of both metal oxides showed similar patterns attributed to simultaneous charge-storage mechanisms of electric double-layer in R-TNTs and pseudocapacitance in the metal oxides. Galvanostatic charge-discharge showed Mn2O3/R-TNTs exhibits higher specific capacitance of 37.0 mF cm-2 compared to Co3O4/R-TNTs of 16.9 mF cm-2 at 0.1 mA cm-2. Moreover, these deposited samples also exhibit good electrochemical stability by retaining 87% of the initial capacity over 1000 cycles

Titania nanotubes synthesised via the electrochemical anodisation method: synthesis and supercapacitor applications

Titania nanotube is gaining tremendous interest for its unique features including high surface area, ion-exchange ability, photocatalytic potential and prominent electrical properties. Many attempts were made to manipulate the unique properties of titania nanotubes for supercapacitor application. In this review a comprehensive list of literatures on fabrication of titania nanotubes via anodisation method in fluoride-based electrolytes and its application as supercapacitor are discussed. This review shows that the nanotube morphology can be optimized by varying the anodisation parameter such as electrolyte concentration, pH, voltage, and bath temperature. The review also includes studies on the application of titania nanotubes as supercapacitor on improving the specific capacitance value by doping with metal oxides and conducting polymers

Biologically-active exosomes in plasma of AML patients inhibit innate immunity and promote leukemia progression

AML patients are reported to have impairments of immune cells which contribute to leukemia progression. Tumor-derived exosomes (TEX) have recently emerged as carriers of the molecular and genetic cargo with potent immunosuppressive properties. We showed that plasma of newly-diagnosed AML patients prior to any therapy contained high levels of exosomal proteins relative to those in plasma of normal donors (NC). AML exosomes were enriched in membrane-associated TGF-β1, MICA/MICB and markers of myeloid blasts. We hypothesize that these plasma-derived virus-size (30-100nm) membrane-bound vesicles operating in AML deliver suppressive signals to immune cells and thus may promote leukemia progression

Titania Nanotubes Synthesised via the Electrochemical Anodisation Method: Synthesis and Supercapacitor Applications

Titania nanotube is gaining tremendous interest for its unique features including high surface area, ion-exchange ability, photocatalytic potential and prominent electrical properties. Many attempts were made to manipulate the unique properties of titania nanotubes for supercapacitor application. In this review a comprehensive list of literatures on fabrication of titania nanotubes via anodisation method in fluoride-based electrolytes and its application as supercapacitor are discussed. This review shows that the nanotube morphology can be optimized by varying the anodisation parameter such as electrolyte concentration, pH, voltage, and bath temperature. The review also includes studies on the application of titania nanotubes as supercapacitor on improving the specific capacitance value by doping with metal oxides and conducting polymers

Pairing Inversion via Non-degenerate Auxiliary Pairings

The security of pairing-based cryptosystems is closely related to the difficulty of the pairing inversion problem(PI). In this paper, we discuss the difficulty of pairing inversion on the generalized ate pairings of Vercauteren. First, we provide a simpler approach for PI by generalizing and simplifying Kanayama-Okamoto’s approach; our approach involves modifications of exponentiation inversion(EI) and Miller inversion(MI), via an “auxiliary” pairing. Then we provide a complexity of the modified MI, showing that the complexity depends on the sum-norm of the integer vector defining the auxiliary pairing. Next, we observe that degenerate auxiliary pairings expect to make modified EI harder. We provide a sufficient condition on the integer vector, in terms of its max norm, so that the corresponding auxiliary paring is non-degenerate. Finally, we define an infinite set of curve parameters, which includes those of typical pairing friendly curves, and we show that, within those parameters, PI of arbitrarily given generalized ate pairing can be reduced to modified EI in polynomial time

Quantum dot-sensitized solar cell based on nano-TiO2 electrodes

Quantum dots-sensitized solar cell (QDSSC) is one of the third generation solar cell that is the most promising low cost, easy to manufacture and highly efficient solar cell. Compared to Dye-sensitized solar cell (DSSC), quantum dots (QDs) of QDSSC has a narrow bandgap and possess excellent properties such as tunable band gaps, strong light absorption and high multiple electron generation. Titanium dioxide or titania (TiO2) is an oxides semiconductor material that is frequently used as a photoanode in this photovoltaic system due to high stability under visible light illumination. TiO2 is also known as a good photocatalyst and an excellent choice in environmental purification. The efficiencies of electron injection and light harvesting in QDSSC are affected by the nature, size morphology, and quantity of this nanomaterial. In this review, the concept and principles of the QDSSCs are reviewed. The preparation and fabrication method ofTiO2 electrode in QDSSC are also discussed. It is worthwhile to know the architecture of TiO2 in order to enhance the efficiency of QDSSC

Quantum Dot-sensitized Solar Cell Based on nano-TiO2 Electrode

Quantum dots-sensitized solar cell (QDSSC) is one of the third generation solar cell that is the most promising low cost, easy to manufacture and highly efficient solar cell. Compared to Dyesensitized solar cell (DSSC), quantum dots (QDs) of QDSSC has a narrow bandgap and possess excellent properties such as tunable band gaps, strong light absorption and high multiple electron generation. Titanium dioxide or titania (TiO2) is an oxides semiconductor material that is frequently used as a photoanode in this photovoltaic system due to high stability under visible light illumination. TiO2 is also known as a good photocatalyst and an excellent choice in environmental purification. The efficiencies of electron injection and light harvesting in QDSSC are affected by the nature, size morphology, and quantity of this nanomaterial. In this review, the concept and principles of the QDSSCs are reviewed. The preparation and fabrication method ofTiO2 electrode in QDSSC are also discussed. It is worthwhile to know the architecture of TiO2 in order to enhance the efficiency of QDSSC