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A novel process has been developed to synthesize MgH

A flip-flop circuit hardened against soft errors is presented in this paper. This design is an improved version of Quatro for further enhanced soft-error resilience by integrating the guard-gate technique. The proposed design, as well as reference Quatro and regular flip-flops, was implemented and manufactured in a 65-nm CMOS bulk technology. Experimental characterization results of their alpha and heavy ions soft-error rates verified the superior hardening performance of the proposed design over the other two circuits.

Pulsed laser and heavy-ion experiments were carried out on a commercial-off-the-shelf DC/DC pulse width modulation controller to study the equivalent laser Linear Energy Transfer (LET) at wavelengths of 750 nm, 800 nm, 850 nm and 920 nm. The laser experiments showed that the shorter wavelength laser has smaller threshold energy to generate single-event transient pulses. The cross-sections versus heavy-ion LET and laser energy per pulse were obtained and correlated. The heavy-ion and laser cross-sections fit well considering the effects of metal layers on the chip. The results of this research facilitate the future pulsed laser testing by providing explicit coefficients to evaluate the equivalent laser LET, which can be used to replace costly heavy-ion testing.

As the largest RNA virus, coronavirus replication employs complex mechanisms and involves various viral and cellular proteins. The first open reading frame of the coronavirus genome encodes a large polyprotein, which is processed into a number of viral proteins required for viral replication directly or indirectly. These proteins include the RNA-dependent RNA polymerase (RdRp), RNA helicase, proteases, metal-binding proteins, and a number of other proteins of unknown function. Genetic studies suggest that most of these proteins are involved in viral RNA replication. In addition to viral proteins, several cellular proteins, such as heterogeneous nuclear ribonucleoprotein (hnRNP) A1, polypyrimidine-tract-binding (PTB) protein, poly(A)-binding protein (PABP), and mitochondrial aconitase (m-aconitase), have been identified to interact with the critical cis-acting elements of coronavirus replication. Like many other RNA viruses, coronavirus may subvert these cellular proteins from cellular RNA processing or translation machineries to play a role in viral replication.

As the largest RNA virus, coronavirus replication employs complex mechanisms and involves various viral and cellular proteins. The first open reading frame of the coronavirus genome encodes a large polyprotein, which is processed into a number of viral proteins required for viral replication directly or indirectly. These proteins include the RNA-dependent RNA polymerase (RdRp), RNA helicase, proteases, metal-binding proteins, and a number of other proteins of unknown function. Genetic studies suggest that most of these proteins are involved in viral RNA replication. In addition to viral proteins, several cellular proteins, such as heterogeneous nuclear ribonucleoprotein (hnRNP) A1, polypyrimidine-tract-binding (PTB) protein, poly(A)-binding protein (PABP), and mitochondrial aconitase (m-aconitase), have been identified to interact with the critical cis-acting elements of coronavirus replication. Like many other RNA viruses, coronavirus may subvert these cellular proteins from cellular RNA processing or translation machineries to play a role in viral replication.

To understand the alterations of Rb tumor suppressor gene and the relationship between defects in the Rb and p53 pathways in human esophageal carcinogenesis, we examined the loss of heterozygosity (LOH) of the Rb gene and immunohistochemical staining of pRb protein in 56 esophageal squamous cell carcinoma specimens and related the results to the p53 gene alterations. Using four introgenic polymorphic markers as probes, we observed LOH of the Rb gene in 30 of the 55 informative tumor samples. Immunohistochemical analysis revealed different patterns of pRb expression among the tumor samples. In the 56 cases, 16 displayed extensive pRb staining comparable to that of the adjacent normal epithelia, whereas 33 showed either significantly decreased or no pRb staining and 7 had a focal staining pattern reflecting heterogeneous cancer nests in the tumor with respect to Rb status. In the tumor samples containing Rb LOH, 90% showed low or no pRb expression, whereas in samples without Rb LOH, only 20% had altered pRb expression. There was a strong association between LOH of the Rb gene and alteration of pRb expression in our samples (P0.0001), suggesting LOH is a main event leading to Rb inactivation. We found that Rb LOH was more frequent in tumors with p53 mutations (P0.05), which occurred in 31 of the 49 cases analyzed. When the status of Rb and p53 alterations was evaluated by the combined results of immunohistochemical and genetic analyses, we found that alteration of Rb and p53 had an even stronger association in our esophageal squamous cell carcinoma samples (P = 0.0015). Among the 51 cases in which both the Rb and p53 status were determined, 31 contained alterations in both genes, and only 5 and 6 cases were altered in only Rb and only p53, respectively. Our results suggest that defects in the Rb and p53 pathways and their potential synergistic effect in deregulating cell cycle and apoptosis are major mechanisms for esophageal carcinogenesis.

Accumulation of p53 protein occurs in human oesophageal precancerous lesions and even in near-normal oesophageal epithelium. In some instances, p53 gene mutations have been detected. In many of the cases of p53 protein accumulation in early lesions, however, p53 mutations were not detected due to either the lack of mutation or the low abundance of cells with a mutation. In order to enrich p53 immunostain-positive cells for single strand conformation polymorphism (SSCP) analysis and DNA sequencing, an immunohisto-selective sequencing (IHSS) method was developed. Anti-p53 antibody-peroxidase stained oesophageal tissue sections were subjected to ultraviolet (UV) irradiation to damage the DNA in p53 immunostain-negative cells. The immunostain protected p53 immunostain-positive cells from the UV light and thus preserved the DNA in those cells for PCR amplification. Comparison of the SSCP results from sections with and without UV treatment showed that the IHSS method selectively enriched p53 immunostain-positive cells. With this method, we could analyse mutations in samples with as few as 30 p53 immunostain-positive cells per tissue section. Analysis was carried out on tissues with precancerous lesions from six surgically-resected oesophageal specimens and 13 oesophageal biopsies from symptom-free subjects. The results of mutation analysis for some of the samples were confirmed by microdissection to enrich the p53-positive cells. The mutations in tissues with precancerous lesions were compared with those in the corresponding squamous cell carcinomas. The IHSS method is shown to be a simple and effective way to analyse mutations in p53 immunostain-positive cells. IHSS may also be a general method for molecular analysis of biological specimens after immunohistochemical staining.

Previous studies in our laboratory showed that decaffeinated green tea and black tea extracts inhibited 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced tumorigenicity in A/J female mice. In order to understand the mechanism of the inhibitory action, we examined the effects of decaffeinated green tea, black tea, and tea components on the metabolic activation of NNK in vitro and in vivo in this animal model. When added to incubation mixtures containing mouse lung microsomes, decaffeinated green tea and black tea extracts and their fractions, at concentrations up to 0.4 mg/ml, inhibited NNK oxidation and NNK-induced DNA methylation. Among the tea components examined, (-)-epigallocatechin-3-gallate was the most potent inhibitor with 50% inhibitory concentrations of about 0.12 mM for both NNK oxidation and DNA methylation. At these concentrations, (-)-epigallocatechin-3-gallate inhibited the catalytic activities of several P450 enzymes and was more potent against P450 1A and 2B1 than 2E1. When decaffeinated green or black tea extracts were given to female A/J mice as the sole source of drinking fluid before an i.p. injection of NNK (100 mg/kg body weight), a statistically significant inhibition of lung DNA methylation, however, was not observed, although a significant reduction in lung tumor multiplicity was observed. The results suggest that, although inhibition of the metabolic activation of NNK and the subsequent DNA alkylation by tea extracts can be demonstrated in vitro, this mechanism may not be important for the inhibitory action of tea against lung tumorigenesis.

It is well established that high concentrations of sugar in the lens of the eye eventually lead to fiber cell destruction and cataracts. In these studies the decrease in crystallin mRNAs was quantified as a result of influx of high concentrations of galactose into the lens of rats. The alpha A-, alpha B1-, and gamma-crystallin mRNA concentrations were assessed in normal lens and in lens undergoing development of sugar cataracts by northern blot and in situ hybridization methods. In a normal, 28-day-old lens, alpha A-crystallin mRNA accumulated to high levels throughout the fiberplasm, and alpha B-crystallin mRNA was present at low levels in epithelial cells, with increased expression in elongating epithelial and fiber cells. The beta B1-crystallin mRNA was distributed to about the same grain density throughout the fiberplasm but at significantly lower levels than alpha A-crystallin mRNA. The gamma-crystallin mRNA first emerged in the terminally differentiated fiber cell, with insignificant amounts detected in the elongating epithelial and fiber cells at the bow. Measurements of hybridization levels on the same RNA population isolated from a single lens showed that in the controls, alpha A-crystallin mRNA comprised about ten times the level of alpha B-crystallin mRNA and twice the level of beta B1- and gamma-crystallin mRNAs. In the cataractous lens the rate of decrease in the concentrations of alpha A-, alpha B- and beta B1-crystallin mRNAs was the same; the decrease in gamma-crystallin mRNA was far more severe. By 20 days of feeding of galactose, at the age of 48 days, gamma-crystallin mRNA diminished to about 9% of the control levels, alpha A-crystallin mRNA to 49%, alpha B-crystallin mRNA to 55%, and beta B1-crystallin mRNA to 65%. In the normal lens, at 48 days of age, the levels of alpha A-, alpha B-, and beta B1-crystallin mRNAs showed no significant changes; the gamma-crystallin mRNA level decreased significantly, to about 70% of the day-28 level, the time at which galactose feeding began. Overall, these data suggest that the loss in crystallin mRNAs in response to the development of galactose cataracts follows this order of decline: gamma greater than alpha B greater than alpha A greater than beta B1.

The reaction of incorporation of fluoride into tooth enamel from NH4F varnish, and Duaphat were measured using SEMq2 in vitro. Level of enamel uptake of fluoride was highest in teeth treated with NH4F varnish. Average depth of fluoride penetrated into enamel was more than 80 microns from the two varnishes. Prolonged coating duration from 24 hours to 1 week did not increase uptake and penetration of fluoride from both varnishes. The NH4F varnish was found to be superior to Duraphat in terms of inhibiting artificial caries lesion formation (P less than 0.001).