Theory and data for simulating fine-scale human movement in an urban environment

Individual-based models of infectious disease transmission depend on accurate quantification of fine-scale patterns of human movement. Existing models of movement either pertain to overly coarse scales, simulate some aspects of movement but not others, or were designed specifically for populations in developed countries. Here, we propose a generalizable framework for simulating the locations that an individual visits, time allocation across those locations, and population-level variation therein. As a case study, we fit alternative models for each of five aspects of movement (number, distance from home and types of locations visited; frequency and duration of visits) to interview data from 157 residents of the city of Iquitos, Peru. Comparison of alternative models showed that location type and distance from home were significant determinants of the locations that individuals visited and how much time they spent there. We also found that for most locations, residents of two neighbourhoods displayed indistinguishable preferences for visiting locations at various distances, despite differing distributions of locations around those neighbourhoods. Finally, simulated patterns of time allocation matched the interview data in a number of ways, suggesting that our framework constitutes a sound basis for simulating fine-scale movement and for investigating factors that influence it.     

Nitrate reductase gene involvement in hexachlorobiphenyl dechlorination by Phanerochaete chrysosporium

Polychlorobiphenyl (PCB) degradation usually occurs through reductive dechlorination under anaerobic conditions and phenolic ring cleavage under aerobic conditions. In this paper, we provide evidence of nitrate reductase (NaR) mediated dechlorination of hexachlorobiphenyl (PCB-153) in Phanerochaete chrysosporium under non-ligninolytic condition and the gene involved. The NaR enzyme and its cofactor, molybdenum (Mo), were found to mediate reductive dechlorination of PCBs even in aerobic condition. Tungsten (W), a competitive inhibitor of this enzyme, was found to suppress this dechlorination. Chlorine release assay provided further evidence of this nitrate reductase mediated dechlorination. Commercially available pure NaR enzyme from Aspergillus was used to confirm these results. Through homology search using TBLASTN program, NaR gene was identified, primers were designed and the RT-PCR product was sequenced. The NaR gene was then annotated in the P. chrysosporium genome (GenBank accession no. AY700576). This is the first report regarding the presence of nitrate reductase gene in this fungus with the explanation why this fungus can dechlorinate PCBs even in aerobic condition. These fungal inoculums are used commercially as pellets in sawdust for enhanced bioremediation of PCBs at the risk of depleting soil nitrates. Hence, the addition of nitrates to the pellets will reduce this risk as well as enhance its activity.     

Covalently linked Au nanoparticles to a viral vector: potential for combined photothermal and gene cancer therapy

Hyperthermia can be produced by near-infrared laser irradiation of gold nanoparticles present in tumors and thus induce tumor cell killing via a bystander effect. To be clinically relevant, however, several problems still need to be resolved. In particular, selective delivery and physical targeting of gold nanoparticles to tumor cells are necessary to improve therapeutic selectivity. Considerable progress has been made with respect to retargeting adenoviral vectors for cancer gene therapy. We therefore hypothesized that covalent coupling of gold nanoparticles to retargeted adenoviral vectors would allow selective delivery of the nanoparticles to tumor cells, thus feasibilizing hyperthermia and gene therapy as a combinatorial therapeutic approach. For this, sulfo-N-hydroxysuccinimide labeled gold nanoparticles were reacted to adenoviral vectors encoding a luciferase reporter gene driven by the cytomegalovirus promoter (AdCMVLuc). We herein demonstrate that covalent coupling could be achieved, while retaining virus infectivity and ability to retarget tumor-associated antigens. These results indicate the possibility of using adenoviral vectors as carriers for gold nanoparticles.     

亚利桑那州立大学跨学科科技馆1号楼（ISTB1）

项目背景 在校长Michael Crow先生的带领下亚利桑那州立大学开始为新学术研究模式奠定基础。这个项目由亚利桑那州立大学董事会下的一个新研究组织赞助建设它致力于多学科的综合．从而推动各学科的动态与协同发展．最终达到促进亚利桑那州科学与经济发展的效果。     

Using chemical and isotopic data to quantify ionic trapping of injected carbon dioxide in oil field brines

Injection of carbon dioxide into depleted oil fields or deep saline aquifers represents one of the most promising means of long-term storage of this greenhouse gas. While the ultimate goal of CO2 injection in the subsurface is mineral storage of CO2 as carbonates, short-term (<50 year) storage of injected CO2 is most likely to be accomplished by ionic trapping of CO2 as bicarbonate ions (HCO3-) and hydrogeological trapping of molecular CO2. Here, we demonstrate a technique for quantifying ionic trapping of injected CO2 as HCO3- using geochemical data collected prior to and during 40 months of CO2 injection into a hydrocarbon reservoir at the International Energy Agency (IEA) Weyburn CO2 Monitoring and Storage Project, Saskatchewan, Canada. As a result of injection of CO2 with a low carbon isotope ratio (delta13C value), fluid and gas samples from four selected production wells showed an increase in HCO3- concentration and a decrease in delta13C values of HCO3- and CO2 over the observation period. Isotope and mass balance calculations indicate that, after 40 months of injection, approximately 80% of the HCO3- in the reservoir brines sampled from the four wells formed via dissolution and dissociation of injected CO2. This chemical and isotopic technique should be applicable to CO2 injection and storage in oil fields and in deep saline aquifers, provided there is sufficient carbon isotopic distinction between injected CO2 and baseline aquifer HCO3- and CO2.     

Potential pitfalls of initiating a newborn hearing screening program

To compare auditory and visual P300 amplitude and latency magnitudes and topographies in patients with narcolepsy and normal subjects, 20 patients with polysomnographically-confirmed narcolepsy and 40 normal subjects were administered auditory and visual P300 testing using 31 evenly spaced scalp electrodes. Patients with narcolepsy were then administered baseline polysomnograms and objective (MSLT, Maintenance of Wakefulness Test or MWT) and subjective tests (Epworth Sleepiness Scale, Clinical Global Impression) of daytime sleepiness. Patients had longer 31-electrode mean age-adjusted auditory P300 latencies (406.0 +/- 27.8 vs. 385.7 +/- 28.9 ms, p = 0.012) and visual P300 latencies (427.3 +/- 29.0 vs. 411.4 +/- 27.7 ms., p = 0.044) than 40 normal subjects in the same age range. Age-adjusted auditory P300 latency was correlated with MWT (r = -0.49, p = 0.028), but not with any other clinical variable or measure of sleepiness. Age-adjusted visual P300 latency was not correlated with any clinical variable or measure of sleepiness. Patients with narcolepsy had longer auditory and visual P300 latencies than normal subjects.     

Ejection fraction by radionuclide ventriculography and contrast left ventriculogram. A tale of two techniques. SAVE Investigators. Survival and Ventricular Enlargement

OBJECTIVES: We assessed the abilities of two methods to measure ejection fraction (EF)-radionuclide ventriculography (RVG) and contrast left ventriculography (Cath-EFa) to predict cardiovascular events. BACKGROUND: Both RVG and Cath-EFa are commonly used methods to measure left ventricular performance and assess prognosis. Their comparative abilities to predict clinical events have not been reported. METHODS: Both RVG EF and Cath-EFa were measured within 16 days of myocardial infarction (MI) in 688 patients. The results were divided into terciles. Prognosis by terciles was assessed for each technique. A multivariate analysis was performed to determine which EF measurement was a better predictor of prognosis. RESULTS: Average RVG-EF was 32%+/-7, while Cath-EFa was 42%+/-10. Both RVG and Cath-EFa were poorly correlated (R=0.42). Event rate declined across terciles with increasing EF for both techniques (events in lowest to highest tercile of Cath-EFa 40.7%, 25.9%, 11.6%, p < 0.001; and RVG-EF 39.9%, 26.1%, 15.6%, p < 0.001). There was concordance of terciles in 303 of 688 patients (44%). When patients in the highest RVG terciles were in the highest Cath-EFa tercile, the event rate was 7%. However, when patients in the highest RVG terciles were in the lowest Cath-EFa tercile, the event rate was 19%. Both Cath-EFa (p < 0.001) and RVG-EF (p < 0.001) were independent predictors of cardiovascular events. CONCLUSIONS: Ejection fraction measured by RVG or during catheterization is a valuable tool in the risk stratification of postinfarct patients. When disagreement is present between clinical impression and measurement by either method, the use of an alternative measurement is warranted and complementary.     

Cardiac outcome in patients with subarachnoid hemorrhage and electrocardiographic abnormalities

OBJECTIVE: Approximately 25% of patients with subarachnoid hemorrhage (SAH) have electrocardiographic (ECG) abnormalities consistent with myocardial ischemia or myocardial infarction (MI), and their cardiac prognosis remains unclear. The objective of this study was to determine the cardiac and all-cause mortality rate of a series of patients with SAH with ECG changes consistent with ischemia or MI. METHODS: Using an existing database of patients with SAH and predetermined ECG criteria for ischemia or MI, a study group of patients with abnormal ECG results within 3 days of presentation and before aneurysm surgery was identified. Database patients without abnormal ECG results served as a control group. Cardiac mortality, defined as death resulting from arrhythmia, congestive heart failure, or cardiogenic shock, was assessed by chart review. RESULTS: Of 439 patients with SAH in the database, 58 met the criteria for the study group. Forty-one of these patients were treated neurosurgically. No deaths resulting from cardiac causes occurred, and 20 patients died as a result of noncardiac causes. In a multivariable analysis, age older than 65 years and Hunt and Hess grade of at least 3 were predictive of all-cause mortality. ECG abnormalities, however, were not a statistically significant predictor. CONCLUSION: In patients with SAH and ECG readings consistent with ischemia or MI, the risk of death resulting from cardiac causes is low, with or without aneurysm surgery. The ECG abnormalities are associated with more severe neurological injury but are not independently predictive of all-cause mortality.     

Secondary hypertension and clinical genetics: usual presentation with unusual diagnosis

A transjugular central venous catheter was inadvertently sutured to the wall of the right atrium in a 63-year-old female during coronary bypass surgery. Using two nitinol Goose Neck snares via a transfemoral and a transjugular approach the catheter was severed into two pieces and retrieved percutaneously.