MA

thesisThere were at least two types of chemoautotrophic thiobacilli found in the leaching streams of Bingham Canyon min dump. One of these organisms oxidizes free sulfur to sulfuric acid which reaction is its energy reaction. This organism is very similar to Thiobacillus thiooxidans. The other organism oxidizes ferrous to ferric ion as its initial energy reaction and is similar to thiobacillus ferrooxidans. These two bacterial strains complement each other in that T. thiooxidans produces acid which keeps the ferric ion produced by T. ferrooxidans in solution, thereby forming an effective acidic ferric sulfate leaching solution for copper minerals. In addition to these two types of chemoautotrophs, a yeast-like organism was found in every location of the Bingham mine dump waters. The cell biology and physiology of these yeast-type organisms were studied. It was found not to be a chemoautotrophic, but an acidophilic heterotroph. The microbial population in the mine water samples suggests the coexistence of a balanced ecological system in which carbon fixation is dependent on chemoautotrophic bacteria. Acidophilic heterotrophs, utilizing organic matter as their energy and carbon source, are acting to keep the organic content of leach waters at a low concentration favorable to the development of chemoautotrophs. Three different counting techniques, such as a Petroff-Hausser counting technique, the silica gel plate counting technique and the radioisotope labeling technique for the enumeration of the chemoautotrophic thiobacilli were studies. Of these methods, the direct microscopic counts were the only ones found to be satisfactory as the most rapid and relatively reliable method of estimating this type of cell numbers. Statistical evaluation of Petroff-Hausser counting technique was also made to prove the reliability of this method. The correlation between the conversion of ferrous to ferric ion and bacterial growth were studies. It was shown that a given amount of conversion of ferrous to ferric ion over a given time period corresponded to a given increase in the bacterial population. The distribution of Thiobacillus ferrooxidans and their ecological environment in the Bingham mine dump were investigated. It was noted that there was a relationship between the numbers of T. ferrooxidans in leaching systems and the chemical reactions which were known to occur in this process

Total Parenteral Nutrition Treatment in a Diabetic Pregnant Woman Complicated with Hyperemesis Gravidarum, Malnutrition, and Intrauterine Growth Restriction

SummaryObjectiveWe report a case of a pregnant woman with diabetes, complicated with hyperemesis gravidarum, malnutrition, and intrauterine growth restriction, who was treated beneficially with total parenteral nutrition.Case ReportA 26-year-old diabetic nullipara complained of severe nausea and vomiting from early in her pregnancy. Malnutrition developed at about 24 weeks of gestation. In spite of treatment with antiemetics, antihistamine, and vitamin B6, the symptoms persisted, and intrauterine growth restriction eventually developed. Total parenteral nutrition was commenced at 29 weeks of gestation. She delivered a healthy female neonate with a birth body weight of 2,120 g at 36 weeks of gestation by cesarean section. Total parenteral nutrition was gradually tapered off 1 week later, and the mother was discharged from hospital in good condition 10 days after delivery.ConclusionTotal parenteral nutrition may be used to treat diabetic patients with hyperemesis gravidarum who develop malnutrition causing intrauterine growth restriction

Fundamental thickness limit of itinerant ferromagnetic SrRuO3_3 thin films

We report on a fundamental thickness limit of the itinerant ferromagnetic oxide SrRuO$_3$ that might arise from the orbital-selective quantum confinement effects. Experimentally, SrRuO$_3$ films remain metallic even for a thickness of 2 unit cells (uc), but the Curie temperature, T$_C$, starts to decrease at 4 uc and becomes zero at 2 uc. Using the Stoner model, we attributed the T$_C$ decrease to a decrease in the density of states (N$_o$). Namely, in the thin film geometry, the hybridized Ru-d$_yz,zx$ orbitals are terminated by top and bottom interfaces, resulting in quantum confinement and reduction of N$_o$.Comment: 20 pages, 4 figure

Secreted APP Regulates the Function of Full-Length APP in Neurite Outgrowth Through Interaction With Integrin Beta1

Background: β-Amyloid precursor protein (APP) has been reported to play a role in the outgrowth of neurites from cultured neurons. Both cell-surface APP and its soluble, ectodomain cleavage product (APPs-α) have been implicated in regulating the length and branching of neurites in a variety of assays, but the mechanism by which APP performs this function is not understood. Results: Here, we report that APP is required for proper neurite outgrowth in a cell autonomous manner, both in vitro and in vivo. Neurons that lack APP undergo elongation of their longest neurite. Deletion of APLP1 or APLP2, homologues of APP, likewise stimulates neurite lengthening. Intriguingly, wild-type neurons exposed to APPs-α, the principal cleavage product of APP, also undergo neurite elongation. However, APPs-α is unable to stimulate neurite elongation in the absence of cellular APP expression. The outgrowth-enhancing effects of both APPs-α and the deletion of APP are inhibited by blocking antibodies to Integrin β1 (Itgβ1). Moreover, full length APP interacts biochemically with Itgβ1, and APPs-α can interfere with this binding. Conclusion: Our findings indicate that APPs-α regulates the function of APP in neurite outgrowth via the novel mechanism of competing with the binding of APP to Itgβ1

The potential application of ultra-nanocrystalline diamond films for heavy ion irradiation detection

[[abstract]]The potential of utilizing the ultra-nanocrystalline (UNCD) films for detecting the Au-ion irradiation was investigated. When the fluence for Au-ion irradiation is lower than the critical value (fc = 5.0 × 1012 ions/cm2) the turn-on field for electron field emission (EFE) process of the UNCD films decreased systematically with the increase in fluence that is correlated with the increase in sp2-bonded phase (π*-band in EELS) due to the Au-ion irradiation. The EFE properties changed irregularly, when the fluence for Au-ion irradiation exceeds this critical value. The transmission electron microscopic microstructural examinations, in conjunction with EELS spectroscopic studies, reveal that the structural change preferentially occurred in the diamond-to-Si interface for the samples experienced over critical fluence of Au-ion irradiation, viz. the crystalline SiC phase was induced in the interfacial region and the thickness of the interface decreased. These observations implied that the UNCD films could be used as irradiation detectors when the fluence for Au-ion irradiation does not exceed such a critical value.[[incitationindex]]SCI[[booktype]]電子

Efficient and facile delivery of gold nanoparticles in vivo using dissolvable microneedles for contrast-enhanced optical coherence tomography

Obtaining sufficient contrast is an indispensable requirement for detecting early stage cancer using optical coherence tomography (OCT), an emerging diagnostic tool that detects abnormal lesions with micrometer resolutions in real time. PEGylated gold nanoparticles (Au NPs; 87 nm in diameter) were formulated in aqueous dissolvable microneedles (dMNs; 200 μm height) for efficient, precisely controlled, and convenient delivery of Au NPs into hamster oral tissue in vivo. The Au NPs were then further briefly dissipated by ultrasound (US). The results showed 33% and 20% increase in average optical scattering intensity (contrast level) in dysplastic and normal tissues, respectively, and pinpointed pathological structures of early stage oral cancer were also identified by the highly convenient and efficient administration of Au NPs in a novel delivery platform

Recent Outbreak of Dengue in Taiwan

In 1987 a dengue outbreak occurred in southern Taiwan, and it persisted throughout the year 1988. Although some cases were reported yearly since then it did not constitute an epidemic as severe as that of 1988. During the period from November 1987 to 30 June 1993, a total of 5,168 serologically or virologically confirmed cases was detected. Of all the cases, 5,085 were considered locally infected, and 83 imported. The proportions of indigenous cases to imported cases were 527 to unknown in 1987, 4,389 to unknown in 1988, 16 to 19 in 1989, 0 to 10 in 1990, 149 to 26 in 1991, 4 to 19 in 1992, and 0 to 9 in 1993. The sources of the imported cases were Thailand (54 cases=65.1%), Philippines (11=13.3%), Singapore (8=9.6%), Indonesia (5=6%), Malaysia (2=2.4%), Vietnam (1=1.2%), India (1=1.2%) and Sri Lanka (1=1.2%). The dengue viruses were isolated both from mosquitoes and humans. Nine D-1 virus isolates were obtained from female mosquitoes of Aedes aegypti among the nine species of mosquitoes collected in houses in 1987 and 1988. The virus isolates from humans were 298 D-1 and 5 D-2 in 1987, 3,534 D-1, 3 D-4 and 1 D-3 in 1988, 5 D-1, 2 D-2 and 1 D-4 in 1989, 1 D-1 and 1 D-2 in 1990, 16 D-1 and 4 D-3 in 1991, and 2 D-1 and 2 D-3 in 1992

Shorter GT repeat polymorphism in the heme oxygenase-1 gene promoter has protective effect on ischemic stroke in dyslipidemia patients

<p>Abstract</p> <p>Background</p> <p>The microsatellite polymorphism of heme oxygenase (HO)-1 gene promoter has been shown to be associated with the susceptibility to ischemic event, including coronary artery disease (CAD), myocardial infarction, and peripheral vascular disease. We aimed to examine whether the length of (GT)_nrepeats in HO-1 gene promoter is associated with ischemic stroke in people with CAD risk factors, especially low level of HDL.</p> <p>Methods</p> <p>A total of 183 consecutive firstever ischemic stroke inpatients and 164 non-stroke patients were screened for the length of (GT)_nrepeats in HO-1 promoter. The long (L) and short (S) genotype are defined as the averaged repeat number >26 and ≦26, respectively.</p> <p>Results</p> <p>Stroke patients tended to have more proportions of hypertension, diabetics and genotype L, than those of genotype S. Patients with genotype L of HO-1 gene promoter have higher stroke risk in comparison with genotype S especially in dyslipidemia individuals. The significant differences on stroke risk in multivariate odds ratios were found especially in people with low HDL-C levels.</p> <p>Conclusions</p> <p>Subjects carrying longer (GT)_nrepeats in HO-1 gene promoter may have greater susceptibility to develop cerebral ischemic only in the presence of low HDL-C, suggesting the protective effects in HO-1 genotype S in the process of ischemic stroke, particularly in subjects with poor HDL-C status.</p

Activation of the ATPase activity of hsp90 by the stress-regulated cochaperone aha1

Client protein activation by Hsp90 involves a plethora of cochaperones whose roles are poorly defined. A ubiquitous family of stress-regulated proteins have been identified (Aha1, activator of Hsp90 ATPase) that bind directly to Hsp90 and are required for the in vivo Hsp90-dependent activation of clients such as v-Src, implicating them as cochaperones of the Hsp90 system. In vitro, Aha1 and its shorter homolog, Hch1, stimulate the inherent ATPase activity of yeast and human Hsp90. The identification of these Hsp90 cochaperone activators adds to the complex roles of cochaperones in regulating the ATPase-coupled conformational changes of the Hsp90 chaperone cycle

Linear Magnetoelectric Phase in Ultrathin MnPS₃ Probed by Optical Second Harmonic Generation

The transition metal thiophosphates MPS₃ (M=Mn, Fe, Ni) are a class of van der Waals stacked insulating antiferromagnets that can be exfoliated down to the ultrathin limit. MnPS₃ is particularly interesting because its Néel ordered state breaks both spatial-inversion and time-reversal symmetries, allowing for a linear magnetoelectric phase that is rare among van der Waals materials. However, it is unknown whether this unique magnetic structure of bulk MnPS₃ remains stable in the ultrathin limit. Using optical second harmonic generation rotational anisotropy, we show that long-range linear magnetoelectric type Néel order in MnPS₃ persists down to at least 5.3 nm thickness. However an unusual mirror symmetry breaking develops in ultrathin samples on SiO₂ substrates that is absent in bulk materials, which is likely related to substrate induced strain