The Effect of Film Thickness on the Gas Sensing Properties of Ultra-Thin TiO2 Films Deposited by Atomic Layer Deposition.

Analyte sensitivity for gas sensors based on semiconducting metal oxides should be highly dependent on the film thickness, particularly when that thickness is on the order of the Debye length. This thickness dependence has previously been demonstrated for SnO2 and inferred for TiO2. In this paper, TiO2 thin films have been prepared by Atomic Layer Deposition (ALD) using titanium isopropoxide and water as precursors. The deposition process was performed on standard alumina gas sensor platforms and microscope slides (for analysis purposes), at a temperature of 200 °C. The TiO2 films were exposed to different concentrations of CO, CH4, NO2, NH3 and SO2 to evaluate their gas sensitivities. These experiments showed that the TiO2 film thickness played a dominant role within the conduction mechanism and the pattern of response for the electrical resistance towards CH4 and NH3 exposure indicated typical n-type semiconducting behavior. The effect of relative humidity on the gas sensitivity has also been demonstrated.

Chemical vapour deposition (CVD) of nickel oxide using the novel nickel dialkylaminoalkoxide precursor [Ni(dmamp')2] (dmamp' = 2-dimethylamino-2-methyl-1-propanolate).

Nickel oxide (NiO) has good optical transparency and wide band-gap, and due to the particular alignment of valence and conduction band energies with typical current collector materials has been used in solar cells as an efficient hole transport-electron blocking layer, where it is most commonly deposited via sol-gel or directly deposited as nanoparticles. An attractive alternative approach is via vapour deposition. This paper describes the chemical vapour deposition of p-type nickel oxide (NiO) thin films using the new nickel CVD precursor [Ni(dmamp')2], which unlike previous examples in literature is synthesised using the readily commercially available dialkylaminoalkoxide ligand dmamp' (2-dimethylamino-2-methyl-1-propanolate). The use of vapour deposited NiO as a blocking layer in a solar-cell device is presented, including benchmarking of performance and potential routes to improving performance to viable levels.

Humidity-Tolerant Ultrathin NiO Gas-Sensing Films.

When the gas sensor active layer film thickness is decreased, increased sensitivity to changes in the adsorbate concentration is expected when measuring the resistance of the layer, in particular when this thickness is on the order of the Debye length of the material (one-tens of nanometers); however, this is demonstrated only for a limited number of materials. Herein, ultrathin NiO films of different thicknesses (8-21 nm) have been deposited via chemical vapor deposition to fabricate gas sensor devices. Sensor performance for a range of NO2 concentrations (800 part-per-billion to 7 part-per-million) was evaluated and an optimum operating temperature of 125 °C determined. The dependence of the potential relative changes with respect to the NO2 concentration and of the sensor signal with respect to the geometrical parameters was qualitatively evaluated to derive a transduction model capable of fitting the experimental results. The selective sensitivity toward NO2 was confirmed by the limited response for different reducing gases, CO, CH4, NH3, and SO2, under optimum operating conditions, and the sensor signal toward NO2 increased with decreasing thickness, demonstrating that the concept of a Debye length dependence of sensitivity is applicable for the p-type semiconductor NiO. In addition, these NiO sensors were exposed to different relative levels of humidity over a wide range of operating temperatures and were found to display humidity tolerance far superior to those in previous reports on SnO2 materials.

Surgical resection for metastatic non-small cell lung cancer to the pancreas.

We report the case of a woman with non-small cell lung cancer (NSCLC) metastatic to the pancreas who underwent pancreatic resection followed by a significant disease-free interval. Resection of NSCLC metastases, other than those to the brain and adrenal gland, are rarely reported. We could not identify any other cases of pancreatic metastasis resection in the literature. This case proves, in principle, that resection of solitary metastatic lesions in certain clinical conditions can be improved regardless of location.

Visual Aspects of Reading Performance in Myalgic Encephalomyelitis (ME).

People with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) report vision-related reading difficulty, although this has not been demonstrated objectively. Accordingly, we assessed reading speed and acuity, including crowded acuity and acuity for isolated words using standardized tests of reading and vision, in 27 ME/CFS patients and matched controls. We found that the ME/CFS group exhibited slower maximum reading speed, and had poorer crowded acuity than controls. Moreover, crowded acuity was significantly associated with maximum reading speed, indicating that patients who were more susceptible to visual crowding read more slowly. These findings suggest vision-related reading difficulty belongs to a class of measureable symptoms for ME/CFS patients.

Optimized Atmospheric-Pressure Chemical Vapor Deposition Thermochromic VO2 Thin Films for Intelligent Window Applications.

Monoclinic vanadium(IV) oxide (VO2) has been widely studied for energy-efficient glazing applications because of its thermochromic properties, displaying a large change in transmission of near-IR wavelengths between the hot and cold states. The optimization of the reaction between VCl4 and ethyl acetate via atmospheric-pressure chemical vapor deposition (APCVD) was shown to produce thin films of monoclinic VO2 with excellent thermochromic properties (ΔT sol = 12%). The tailoring of the thermochromic and visible light transmission was shown to be possible by altering the density and morphology of the deposited films. The films were characterized by X-ray diffraction, atomic-force microscopy, scanning electron microscopy, ellipsometry, and UV-vis spectrometry. This article provides useful design rules for the synthesis of high-quality VO2 thin films by APCVD.

Increased Vulnerability to Pattern-Related Visual Stress in Myalgic Encephalomyelitis.

The objective of this study was to determine vulnerability to pattern-related visual stress in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS). A total of 20 ME/CFS patients and 20 matched (age, gender) controls were recruited to the study. Pattern-related visual stress was determined using the Pattern Glare Test. Participants viewed three patterns, the spatial frequencies (SF) of which were 0.3 (low-SF), 2.3 (mid-SF), and 9.4 (high-SF) cycles per degree (c/deg). They reported the number of distortions they experienced when viewing each pattern. ME/CFS patients exhibited significantly higher pattern glare scores than controls for the mid-SF pattern. Mid-high SF differences were also significantly higher in patients than controls. These findings provide evidence of altered visual perception in ME/CFS. Pattern-related visual stress may represent an identifiable clinical feature of ME/CFS that will prove useful in its diagnosis. However, further research is required to establish if these symptoms reflect ME/CFS-related changes in the functioning of sensory neural pathways.

Beyond black and white: race/ethnicity and health status among older adults.

OBJECTIVES: This study examined physical and mental health, health symptoms, sensory and functional limitations, risk factors, and multimorbidity among older Medicare managed care members to assess disparities associated with race/ethnicity. STUDY DESIGN AND METHODS: We used data on 236,289 older adults from 208 Medicare plans who completed the 2012 Medicare Health Outcomes Survey to compare 14 health indicators across non-Hispanic whites, blacks, American Indians/Alaskan Natives, Asians, Native Hawaiians/Pacific Islanders, multiracial individuals, and Hispanics. Logistic regression models that clustered on the plan estimated the risk of indicators of adverse health and functional status. RESULTS: Even after controlling for key patient sociodemographic factors, race/ethnicity was significantly associated with most adverse health indicators. Except for Asians, all racial/ethnic minority groups were significantly more likely than whites to report poor mental health status, presence of most health symptoms, sensory limitations, and activities-of-daily-living disability. Important differences were observed across racial and ethnic groups. CONCLUSIONS: Despite some exceptions, elders of racial/ethnic minority background are generally at higher risk than non-Hispanic whites for a broad range of adverse health and functional outcomes that are not routinely assessed. Limitations include bias related to self-reported data and respondent recall. Future research should consider ethnic subgroup variations; employing newer techniques to improve estimates for smaller groups; and prioritizing and identifying opportunities for care improvement of diverse enrollee groups by considering specific needs. To improve the health status of the elderly, service delivery targeting the needs of specific population groups, coupled with culturally appropriate care for racial/ ethnic minorities, should also be considered.

Synthesis of iridium and ruthenium complexes with (N,N), (N,O) and (O,O) coordinating bidentate ligands as potential anti-cancer agents.

Several Ru-arene and Ir-Cp* complexes have been prepared incorporating (N,N), (N,O) and (O,O) coordinating bidentate ligands and have been found to be active against both HT-29 and MCF-7 cell lines. By incorporating a biologically active ligand into a metal complex the anti-cancer activity is increased.