Antiferroelectric liquid crystals : hosts and binary mixtures

This thesis details the work carried out towards a doctoral degree in the synthesis, characterisation and evaluation of liquid-crystalline materials possessing antiferroelectric smectic C* (SmCA*) and non-chiral anticlinic smectic C (SmCait) phases. The effects of structural modifications of the materials on the occurrence and stability of the alternating-tilt smectic phases are described. The work was designed to evaluate the potential use of chiral-dopant antiferroelectric mixtures for antiferroelectric liquid crystal display devices (AFLCDs), analogous to the chiral- dopant ferroelectric mixtures used currently in ferroelectric liquid crystal display devices (FLCDs), for fast-switching display device applications. The most suitable materials from those prepared, including both optically active (chiral) dopants and achiral or racemic hosts, were selected and their applications in this novel mixture concept investigated. The switching characteristics of some model chiral-dopant binary mixtures were also studied, and the practical applicabilities of the mixtures developed are discussed

Salicylic Acid, Sulphosalicylic Acid & Salicylamide as Indicators for Direct Titration of Fe3+ with Diethylene Triaminepentaacetic Acid

1119-112

Myc regulates VEGF production in B cells by stimulating initiation of VEGF mRNA translation.

Deregulated c-myc gene expression is associated with many human and animal cancers. Myc overexpression promotes the growth of blood and lymphatic vessels, which is due in part to induction of growth factors including vascular endothelial growth factor (VEGF). We determined that the P493-6 human B-cell line increases VEGF production 10-fold upon Myc overexpression. Myc overexpression in avian B cells similarly resulted in high level VEGF production. Real-time RT-PCR analyses showed that Myc did not alter the VEGF mRNA content of these cell lines, indicating that a post-transcriptional mechanism regulates VEGF production. VEGF mRNA translation was examined by RT-PCR analysis of monosome and polysome sucrose gradient fractions from Myc-on and Myc-off P493-6 cells. Myc increased VEGF mRNA translation initiation, as VEGF mRNA loading onto polysomes increased 14-fold in Myc-on cells, and the number of ribosomes loaded per VEGF mRNA increased threefold. This translational regulation is specific to VEGF mRNA, as total polysomes show the same sucrose gradient profile in Myc-on and Myc-off cells, with no change in the percent ribosomes in polysomes, or in the number of ribosomes per polysomal mRNA. Myc stimulates VEGF production by a rapamycin- and LY294002-sensitive pathway, which does not involve alteration of eIF4E activity

Immune-Related Gene Expression in Two B-Complex Disparate Genetically Inbred Fayoumi Chicken Lines Following Eimeria maxima Infection

To investigate the influence of genetic differences in the MHC on susceptibility to avian coccidiosis, M5.1 and M15.2 B-haplotype-disparate Fayoumi chickens were orally infected with live Eimeria maxima oocysts, and BW gain, fecal oocyst production, and expression of 14 immune-related genes were determined as parameters of protective immunity. Weight loss was reduced and fecal parasite numbers were lower in birds of the M5.1 line compared with M15.2 line birds. Intestinal intraepithelial lymphocytes from M5.1 chickens expressed greater levels of transcripts encoding interferon-γ (IFN-γ), interleukin-1β (IL-1β), IL-6, IL-8, IL-12, IL-15, IL-17A, inducible nitric oxide synthase, and lipopolysaccharide-induced tumor necrosis factor-α factor and lower levels of mRNA for IFN-α, IL-10, IL-17D, NK-lysin, and tumor necrosis factor superfamily 15 compared with the M15.2 line. In the spleen, E. maxima infection was associated with greater expression levels of IFN-γ, IL-15, and IL-8 and lower levels of IL-6, IL-17D, and IL-12 in M5.1 vs. M15.2 birds. These results suggest that genetic determinants within the chicken MHC influence resistance to E. maxima infection by controlling the local and systemic expression of immune-related cytokine and chemokine genes

Assessing the predictive ability of the Suicide Crisis Inventory for near-term suicidal behavior using machine learning approaches

OBJECTIVE: This study explores the prediction of near-term suicidal behavior using machine learning (ML) analyses of the Suicide Crisis Inventory (SCI), which measures the Suicide Crisis Syndrome, a presuicidal mental state. METHODS: SCI data were collected from high-risk psychiatric inpatients (N = 591) grouped based on their short-term suicidal behavior, that is, those who attempted suicide between intake and 1-month follow-up dates (N = 20) and those who did not (N = 571). Data were analyzed using three predictive algorithms (logistic regression, random forest, and gradient boosting) and three sampling approaches (split sample, Synthetic minority oversampling technique, and enhanced bootstrap). RESULTS: The enhanced bootstrap approach considerably outperformed the other sampling approaches, with random forest (98.0% precision; 33.9% recall; 71.0% Area under the precision-recall curve [AUPRC]; and 87.8% Area under the receiver operating characteristic [AUROC]) and gradient boosting (94.0% precision; 48.9% recall; 70.5% AUPRC; and 89.4% AUROC) algorithms performing best in predicting positive cases of near-term suicidal behavior using this dataset. CONCLUSIONS: ML can be useful in analyzing data from psychometric scales, such as the SCI, and for predicting near-term suicidal behavior. However, in cases such as the current analysis where the data are highly imbalanced, the optimal method of measuring performance must be carefully considered and selected

p19/Arf and p53 suppress sentinel lymph node lymphangiogenesis and carcinoma metastasis.

The ability of tumor cells to metastasize is increasingly viewed as an interaction between the primary tumor and host tissues. Deletion of the p19/Arf or p53 tumor suppressor genes accelerates malignant progression and metastatic spread of 7,12-dimethylbenz(a)anthracene (DMBA)/12-O-tetradecanoyl-phorbol-13-acetate (TPA)-induced squamous cell carcinomas, providing a model system to address mechanisms of metastasis. Here, we show that benign pre-metastatic papillomas from wild-type mice trigger lymphangiogenesis within draining lymph nodes, whereas there is no growth of primary tumor lymphatic vessels. Lymph node lymphangiogenesis is greatly accelerated in papilloma-bearing p19/Arf- or p53-deficient mice, which coincides with the greater propensity of these tumors to progress to carcinomas and to metastasize. The extent of accumulation of B cells within the tumor-draining lymph nodes of wild-type mice predicted the level of lymph node lymphangiogenesis and metastatic potential. Arf or p53 deficiency strongly accelerated lymph node immune cell accumulation, in a manner that was associated with the extent of lymph node lymphatic sinus growth. This immune cell accumulation and lymph node lymphangiogenesis phenotype identifies host anti-tumor responses that could drive metastatic spread of cancers via the lymphatics

Experimental investigation of low resistance joints for high field HTS magnets

High-temperature superconducting (HTS) tapes are now commercially available for various magnet applications. Their higher tensile strength enhances strain tolerance, allowing for the winding of smaller diameter coils. The most crucial component in a double pancake winding of a coil is the fabrication of inter-double pancake joints with minimal electrical resistance. This is due to the structural design of REBCO (RE—rare earth) tape, which consists of very thin layers of materials prone to deterioration when exposed to temperatures exceeding the recommended value, optimal joint overlap length, and the selection of solder materials. In this study, we investigated the effects of tape overlap lengths, solder materials, and soldering temperatures on joint resistance. The lowest joint resistance recorded was 18 nΩ, achieved with an overlap length of 150 mm at 4.2 K in a self-field, as reported in this paper for a 3.5 T REBCO coil winding pack

Elevated Rates of Sister Chromatid Exchange at Chromosome Ends

Chromosome ends are known hotspots of meiotic recombination and double-strand breaks. We monitored mitotic sister chromatid exchange (SCE) in telomeres and subtelomeres and found that 17% of all SCE occurs in the terminal 0.1% of the chromosome. Telomeres and subtelomeres are significantly enriched for SCEs, exhibiting rates of SCE per basepair that are at least 1,600 and 160 times greater, respectively, than elsewhere in the genome